GAZA, March 26 (Nidal al-Mughrabi -  Reuters) - Two Israeli soldiers were killed and at least two Palestinians wounded on Friday in what may be the most deadly clash on the Gaza Strip border since Israel ended its offensive there 14 months ago.

The Israeli army said an officer and a conscript were killed in an ambush by Palestinian gunmen against an Israeli military patrol. Two other soldiers were wounded.
Two Palestinians, one a 10-year-old boy, were also wounded, Gaza hospital officials said.

The militant Islamist group Hamas which rules the enclave said its men had fired on Israeli soldiers who crossed into the Strip.
The clash did not appear to be directly linked to the current diplomatic impasse between Israel, the Palestinians and the United States over Israeli settlements of occupied West Bank land and stalled efforts to relaunch peace talks.

Israel unilaterally withdrew from Gaza in 2005.
Hamas has largely held its fire since a costly three-week war with Israel in the opening days of 2009 in which some 1,400 Palestinians, mainly civilians, and 13 Israelis, mainly soldiers, were killed.
But smaller factions have violated the de facto truce by firing rockets and mortars into neighbouring Israeli territory.

Israel said it was holding Hamas accountable for the violence, which made further retaliatory action likely. Hamas is accountable for any activity that takes place from Gaza to Israel. It doesn't matter if it took responsibility or not, a military spokeswoman told reporters.

Hamas took part in the fighting but said its gunmen acted to repel an Israeli incursion.
An Israeli army force raided 500 metres (yards) into Palestinian territory, and was confronted by our gunmen, said Abu Obeida, spokesman for the Hamas armed wing. This was our work, but it was carried out for defence.

Two other groups, Islamic Jihad and al-Aqsa Martyrs Brigades, said their men also took part in the fighting.

The Israeli army spokeswoman said the army unit was fired upon after crossing into Gaza in an operation to dismantle a mine.

EXCHANGE OF FIRE
Witnesses said Friday's exchange of fire began when an explosion, possibly caused by an armour-piercing rocket fired from the nearby Palestinian town of Khan Younis, hit an Israeli army patrol on the central Gazan border.

Backed by tanks, Israeli troops fired back and entered Gazan territory, the witnesses said. Such pursuits are common practice for the Israelis, who try to maintain a buffer zone within the border fence off-limits to Palestinians.

Palestinian sources said there were further casualties but no details were immediately available.
The witnesses said that, during the fighting, soldiers stretchered away a wounded comrade and helicopters came to the scene, apparently for medical evacuations.

The statements by Hamas, Islamic Jihad and al-Aqsa Martyrs Brigades did not make clear who might have carried out the initial ambush on the Israeli patrol.

Tensions have run high along the Gaza frontier this month, with Israel launching repeated air strikes in response to Palestinian rocket attacks, one of which killed a Thai worker in a kibbutz last week.

An Israeli soldier was accidentally shot dead by comrades earlier this month as they rushed to intercept three Palestinian border-jumpers, who were later found to have been going in search of work in Israel.
The last time an Israeli soldier was killed on the Gaza border was 9 days after the offensive ended in January 2009, when a bomb planted by Palestinian gunman exploded.