This was CNBC's live blog tracking developments on the war in Ukraine.

Russia has signaled that it could heavily intensify its attacks on Ukraine, after its defense minister told troops in the Central and Southern command groups to step up their operations "in all directions."

Meanwhile, Ukraine's President Volodymyr Zelenskyy has suspended the head of Ukraine's security service and the prosecutor general.

It was announced on Sunday that Prosecutor General Irina Venediktova and the Head of the SBU (the Security Service of Ukraine) Ivan Bakanov were being suspended after Zelenskyy said that there had been cases of treason discovered in both government agencies.

Ukrainian nuclear power plant official abducted by Russian forces, Ukraine says

A Ukrainian nuclear power plant company said that Russian forces abducted Ihor Kvashnin, the head of the environmental protection service of the Zaporizhia Nuclear Power Plant in southeastern Ukraine.

"They took him to an unknown destination," Energoatom stated on the Telegram messaging platform. "It is still impossible to locate Kvashnin," the company added.

Russian forces took Kvashnin on July 17.

— Amanda Macias

Russia has launched 3,000 missiles, Ukraine's Air Force says

Ukraine's Air Force wrote on Facebook that Russia's military has launched about 3,000 missiles over Ukraine. 

"These are cruise missiles, aviation missiles of the air-to-surface class, missiles fired from operational-tactical complexes, like the Tochka-U and Iskander, as well as Onyx missiles," Ukraine's Air Force wrote on its Facebook page.

The group wrote that Russia is also using old Soviet missiles "against Ukrainian military positions and civilian objects."

— Amanda Macias

Ukraine's first lady to address Congress this week

Ukraine's first lady Olena Zelenska will address the U.S. Congress this week, Speaker Nancy Pelosi's office said in a statement announcing the visit.

Zelenska is expected to deliver a speech on Wednesday at 11 a.m. E.T.

Pelosi invited all members of the House and Senate to attend the address.

— Amanda Macias

NATO's Stoltenberg urges European Parliament to 'stop complaining' and support Ukraine

NATO Secretary General Jens Stoltenberg urged members of the European Parliament to "stop complaining and step up and provide support" to Ukraine.

"The price we pay as the European Union, as NATO is the price we can measure in currency, in money. The price they pay is measured in lives lost every day," Stoltenberg said, adding "We should stop complaining and step up and provide support, full stop."

Stoltenberg said that European Union member countries should aim to provide substantial support to Ukraine for a long time because "the price of not supporting them is much higher."

"It is in our interest to help Ukraine because you have to understand that if Ukraine loses this that's a danger for us," he said.

"If you don't care about the moral aspect of this, supporting the people of Ukraine, you should care about your own security interests," he added.

"Pay for the support, pay for the humanitarian aid, pay the consequences of the economic sanctions, because the alternative is to pay a much higher price later on."

— Amanda Macias

Milley speaks to Ukrainian counterpart and reaffirms U.S. support

U.S. Chairman of the Joint Chiefs of Staff Gen. Mark Milley spoke with his Ukrainian counterpart and reiterated "unwavering support" for Kyiv.

"They discussed the unprovoked and ongoing Russian invasion of Ukraine and exchanged perspectives and assessments," according to a Pentagon readout of the call with Ukrainian Armed Forces Gen. Valery Zaluzhny.

"The chairman once again reaffirmed unwavering support for Ukraine's sovereignty and territorial integrity," the readout added.

— Amanda Macias

Putin says Russia cannot be cut off from rest of world

Russian President Vladimir Putin said it is impossible to cut Russia off from the rest of the world despite several rounds of coordinated global sanctions for the Kremlin's war in Ukraine.

"Clearly, we cannot develop in isolation from the rest of the world, and it won't be like that," Putin said on a video call with government figures, according to Reuters.

"In today's world, you can't just, you know, circle everything with a compass and put up a huge fence. It's just not possible," he added.

The Russian leader said that Moscow will prioritize and develop technological advancements that will help attract investments.

"We must put mechanisms in place in the Russian financial system, in the short term, that provide fast-growing companies with the option to attract domestic capital to finance their development," Putin said.

— Amanda Macias

UN says at least 5,110 killed in Ukraine since start of war

The United Nations has confirmed 5,110 civilian deaths and 6,752 injuries in Ukraine since Russia invaded its ex-Soviet neighbor on Feb. 24.

The Office of the U.N. High Commissioner for Human Rights said the death toll in Ukraine is likely higher, because the armed conflict can delay fatality reports.

The international organization said most of the civilian casualties recorded were caused by the use of explosive weapons with a wide impact area, including shelling from heavy artillery and multiple launch rocket systems, as well as missiles and airstrikes.

— Amanda Macias

Russia using private military company Wagner to reinforce frontlines, UK says

Russia has used private military company Wagner to reinforce frontline forces and to mitigate manning shortfalls and casualties, the U.K.'s Ministry of Defence has said.

"Wagner has almost certainly played a central role in recent fighting, including the capture of Popasna and Lysyschansk. This fighting has inflicted heavy casualties on the group," the ministry said on Twitter on Monday.

Wagner is lowering recruitment standards, the ministry also said in its latest intelligence update, suggesting the state-linked Russian paramilitary group has been "hiring convicts and formerly blacklisted individuals."

Very limited training is made available to new recruits, it added, noting that "this will highly likely impact on the future operational effectiveness of the group and will reduce its value as a prop to the regular Russian forces."

Remarking on tensions between the Wagner Group and Russia's military, the U.K. said that the fact that Wagner head, Yevgeniy Prigozhin, was recently been made a Hero of the Russian Federation for Wagner's performance in Luhansk was likely to exacerbate grievances between the military and Wagner. It is also likely to impact negatively on Russian military morale.

— Holly Ellyatt

Russian state news outfit RT breached impartiality rules on multiple occasions, UK regulator finds

Ofcom, the U.K.'s communications regulator, decided that news and current affairs coverage by Russia's state-sponsored English-language broadcaster RT (formerly Russia Today) in the wake of Russia's invasion of Ukraine breached due impartiality rules on 29 occasions in four days.

When dealing with major matters such as wars or areas of conflict (in these cases, specifically the ongoing conflict in the Donbas region), all Ofcom licensees must comply with the special impartiality requirements in its broadcasting code.

"These rules require broadcasters to take additional steps to preserve due impartiality – namely by including and giving due weight to a wide range of significant views," Ofcom said in a statement Monday, saying these steps were "particularly important in situations where events are changing quickly and potentially harmful disinformation is available online."

Ofcom said it had launched 29 investigations into RT following complaints from viewers and Ofcom's own monitoring of the channel. "Our investigations looked at the due impartiality of 15 RT News bulletins on 27 February 2022, 12 on 1 March 2022, and one on 2 March 2022 as well as the documentary Donbass Yesterday, Today and Tomorrow which was repeated across 1 and 2 March 2022."

"In each case, we found that RT's coverage failed to preserve due impartiality in relation to the conflict in the Donbas region of Ukraine. Ofcom considers that these breaches were serious and repeated, and we are minded to consider them for the imposition of a statutory sanction."

RT is no longer broadcasting in the U.K. as Ofcom revoked RT's broadcast license on March 18 on the basis that the agency did not consider RT's licensee, ANO TV Novosti, fit and proper to hold it.

— Holly Ellyatt

Zelenskyy removes top officials after cases of treason in government agencies

Ukraine's President Volodymyr Zelenskyy suspended the head of Ukraine's security service and the prosecutor general.

It was announced on Sunday that Prosecutor General Irina Venediktova and the Head of the SBU (the Security Service of Ukraine) Ivan Bakanov were being suspended after Zelenskyy said that there had been cases of treason discovered in both government agencies.

"As of today, 651 criminal proceedings have been registered regarding high treason and collaborative activities of employees of prosecutor's offices, pre-trial investigation bodies, and other law enforcement agencies," Zelenskyy said in his nightly address on Sunday. 

He said that "more than 60 employees of the prosecutor's office and the SBU remained in the occupied territory and are working against our state."

Zelenskyy said "all Russian war criminals" would be brought to justice as well as "each of the collaborators" and "all those responsible for terror."

There has been no comment from the officials named by Zelenskyy.

— Holly Ellyatt

Increase operations in all directions, Russia's defense chief tells troops

Russian Defense Minister Sergei Shoigu told the country's armed forces to "intensify" their operations on all fronts, claiming this was to "prevent massive missile and artillery attacks" that he claimed were being launched by Ukrainian forces at civilian infrastructure facilities, the Donbas and other regions.

The remarks by Shoigu, a close ally of President Putin, come after the Ukrainian military said it had carried out a series of successful strikes on Russian ammunition depots and logistics centers in recent weeks.

Shoigu's comments also mark what could be a more aggressive stance by Russia as Western weapons delivered to Ukraine start to have an impact in this phase of war, which has seen severe fighting in the Donbas' two main regions: Luhansk, which is now fully occupied by Russia, and neighboring Donetsk in which Russian forces are trying to advance.

Russia claims it is trying to "liberate" the Donbas, where there is a preponderance of ethnic Russians and where two self-proclaimed "People's Republics" are located. Contrary to Shoigu's claims, there have been multiple instances of Russia striking civilian infrastructure. Last week, there were multiple deaths following missile attacks on central and eastern Ukraine.

— Holly Ellyatt