Israeli helicopters fired into the Gaza Strip on Saturday, killing one Palestinian militant, in what local residents said was the fiercest exchange between Israeli forces and militants since a November truce.
The escalation in Israeli military activity came after Defence Minister Amir Peretz authorised limited strikes just inside Gaza to try to prevent militants from planting explosives, digging tunnels and firing rockets at Israeli towns.
Palestinian President Mahmoud Abbas called on members of his presidential guard and national security forces to step up efforts to prevent the rocket fire so "that our people can lead a safe life".
The presidential guard and national security forces are loyal to Abbas's Fatah faction. Tensions remain high in Gaza between secular Fatah and Hamas despite the formation of their unity government on March 17.
Three Palestinians were wounded in Gaza in separate clashes between Hamas and Fatah gunmen, witnesses and Hamas militants said. Abbas said on Friday that Israeli soldier Gilad Shalit, who was abducted by Gaza militants 10 months ago in a cross-border raid, would be released soon.
Palestinian Information Minister Mustafa Barghouthi said Gaza militants involved in the abduction had provided Israel for the first time with a list of Palestinian prisoners they want Israel to release in exchange for Shalit. "The Palestinian side has done its part in the process and now the ball is the Israeli court," he said.
Israeli helicopters fired at least two missiles near the Jabalya refugee camp in the northern Gaza Strip during the early morning strike, local residents said. An Israeli army spokesman said the helicopters fired at a group of militants who had tried to plant an explosive device near the border fence.
Islamic Jihad said its militants and members of another group had been mounting an operation near the fence when the exchange of fire occurred. Militants said they fired rocket-propelled grenades and automatic weapons at the Israeli forces, and detonated bombs they had planted previously near the border fence.
A member of the Democratic Front for the Liberation of Palestine was killed in the exchange, Islamic Jihad said. At least two other militants were wounded Local residents said Israeli tanks had entered the area but the army denied this.