Israeli troops fatally shot two Palestinians who infiltrated the country from Gaza and attacked soldiers with explosives Sunday night, and in a separate incident killed another Palestinian who tried to breach the border, the military said.
Another Palestinian was detained in the latter incident, and two more were caught trying to cross the border in a third case, the military said.
The Gaza border has been tense in recent weeks, with the Islamic militant group Hamas that rules Gaza urging mass Palestinian protests there every Friday as part of a weeks-long campaign against a decade-old blockade of the territory. The protests have turned violent and 39 Palestinians have been killed during the unrest, which began March 30.
Israel says that it is defending its sovereign border, including nearby communities, and that its troops target only instigators. Israel accuses Hamas, which is sworn to Israel's destruction, of trying to carry out attacks under the guise of the mass protests.
The military said that "two terrorists who infiltrated into Israel hurled explosive devices" at soldiers Sunday night. The soldiers returned fire, killing them.
About a half hour earlier, two Palestinians damaged the security fence and tried to cross into Israel. Troops opened fire, killing one, the military said. The other was detained for questioning, it said.
In a third incident, soldiers spotted two Palestinians trying to breach the border. They were arrested and found to have knives and wire cutters on their persons, the military said.
There was no immediate comment from Hamas in Gaza.
Also Sunday, the Israeli army said most of the deaths of Palestinians during the Gaza unrest have been unintentional. An unidentified senior officer in Israel's southern command told the newspaper Haaretz that snipers have been aiming at protesters' legs, but people have been killed after bending down, when struck by a ricocheting bullet or when a sniper misses the target.
A second senior officer confirmed the report, saying that while there is no exact breakdown, the "overwhelming majority" of deaths were unintentional, including a teenage boy and two Palestinian journalists who apparently were caught in crossfire. He said an exception was Friday, when soldiers opened fire at a large crowd that attempted to break through the border fence, killing three people.
The officer spoke on condition of anonymity under military guidelines.
Israel has been accused by the United Nations, European Union and rights groups of using excessive force against unarmed protesters. Israel says it is aiming only at instigators, and accuses Hamas of using civilians for cover to carry out attacks.
Israel says some of those protesting have tried to damage the border fence or plant explosives along it. Others have hurled improvised explosives and firebombs at soldiers while others have flown kites with burning rags attached to set Israeli fields on fire.
There is considerable fear among Israelis of a mass breach in which Gazans stream across, militants mixed in, wreaking havoc. Israel has warned that anyone approaching the border fence is risking their lives and accused Hamas of cynically exploiting civilians for its agenda.
Hamas has attacked Israelis with suicide bombings, shootings and rockets over the years. For more than a decade the group has tightly controlled Gaza, quashing dissent.
Hamas says the protests are aimed at breaking a crippling border blockade that was imposed by Israel and Egypt after the Islamic militant group overran Gaza in 2007.
The blockade has devastated Gaza's economy, made it virtually impossible for people to enter and exit the territory, and left residents with just a few hours of electricity a day. Tap water is undrinkable and its Mediterranean coast has been polluted with untreated waste. Life in the coastal strip has deteriorated further in recent months, with rising unemployment and grinding poverty.
Other blockade-busting tactics by Hamas have failed over the years, including three cross-border wars with Israel and repeated rounds of unsuccessful power-sharing talks with the West Bank-based Palestinian President Mahmoud Abbas. The last round collapsed, in part because Hamas refused to disarm.
The protests also press for a "return" of Palestinian refugees and their descendants to what is now Israel. Hundreds of thousands of Palestinians fled or were displaced in the 1948 war over Israel's creation.
The protests are to culminate May 15, the anniversary of Israel's founding. Palestinians mark the date as their "nakba," or catastrophe.