Palestinian mourners carry the body of an Islamic Jihad militant
At least two Palestinian militants died and three were hurt in an Israeli army strike in the Gaza Strip, the Israeli army and Palestinian medics said.
The clash took place near the Kissufim border crossing in central Gaza.
The Israeli military says it hit a group of Palestinians laying explosives near Gaza's perimeter fence.
Islamic Jihad, a radical Islamist group, said the Israeli troops entered the Gaza Strip and fired from a helicopter and tanks.
The body of a 23-year-old Islamic Jihad fighter was taken to a Gaza hospital immediately after the fighting.
A second body was later retrieved from the area, it was reported.
The Israeli military said it believed four militants were killed and claimed they were armed with explosives, grenades and assault rifles, the Associated Press news agency reported.
The Israeli military released a photograph of the weapons it said were found.
Gaza medics said only two bodies had been retrieved.
There has been an unsteady ceasefire since Israel ended its assault on Gaza in January 2009.
Palestinians and rights groups say more than 1,400 Gazans died in the conflict, while Israel puts the figure at 1,166. Thirteen Israelis, including three civilians, were killed.
Factions like Islamic Jihad have continued to fire rockets and mortar shells into southern Israel.
Last month a Thai farm worker in Israel was killed by a rocket fired from Gaza - the first such death in a year.
Over roughly the same period, about 90 Palestinians in Gaza have been killed in a mixture of Israeli military operations and border clashes, according to the UN.
Hamas says it has been trying to keep attacks on Israel in check.
Islamic Jihad said that on Sunday police had detained several of its fighters, along with those from another group, and forced them to sign pledges that they would not engage in attacks on Israel, the Associated Press reported.