Israeli forces opened fire at a group of Palestinian gunmen as they tried to cross the Gaza border, the military said on Sunday.
Palestinian medics said they retrieved three bodies from the site and Gaza hospital officials said a fourth man was injured.
“A short while ago, [Israel] troops spotted a number of armed suspects adjacent to the security fence in the northern Gaza Strip. An IDF attack helicopter and a tank fired towards them,” the military said in a statement, using an acronym for the Israeli military.
The incident happened overnight between Saturday and Sunday, shortly after three rockets were fired from Gaza into Israel, one of them landing in a town near the border, the Israeli military and police said. Israel said it was the second rocket attack in 24 hours.
There was no immediate comment from any of the major armed groups in Gaza. No Israeli was hurt.
On Friday, Palestinians in Gaza fired a rocket at Sderot, in what the army said was the first such attack since July 12.
In response, Israeli warplanes struck at least three targets in the Gaza Strip early on Saturday but caused no casualties, a Palestinian security source said.
The strikes hit a Hamas observation post in Beit Hanoun, in the northern Gaza Strip, an unidentified target near Gaza City and open ground near Deir El Balah in the central part of the territory, the source said.
An Israeli army statement mentioned only two strikes, against “underground targets belonging to the Hamas terror organisation in the northern and central Gaza Strip”.
Gaza is ruled by Hamas, which has fought three wars with Israel over the past decade.
Israel pulled its troops and settlers from the territory in 2005 but keeps the enclave under a blockade, citing security concerns.
Tensions along the border are high, with frequent fatalities.
Since March 2018, regular protests and clashes have erupted along the border of the blockaded coastal enclave.
At least 305 Palestinians have been killed by Israeli fire in Gaza or the border area since then, the majority during demonstrations and clashes.
Seven Israelis have also been killed in Gaza-related violence over the same period.