JERUSALEM Palestinian militants in the Gaza Strip fired several rockets into Israel on Tuesday, breaching a five-day-old ceasefire after Israeli troops killed a Palestinian militant leader in the occupied West Bank.
The Islamic Jihad salvo lightly wounded two residents of an Israeli border town and overshadowed a meeting of world powers in Berlin on ways to shore up Palestinian President Mahmoud Abbas as he pursues peace talks with the Jewish state.
"This is a blatant violation of the calm, and we will weigh options," a aide quoted Israeli Prime Minister Ehud Olmert as saying after the rockets struck Sderot.
Hamas, Abbas's Islamist rival which rules Gaza, condemned the West Bank raid but urged fellow factions to hold fire.
"Hamas is keen to maintain the calm," Hamas official Sami Abu Zuhri said.
Fresh Gaza bloodshed could hurt Olmert's bid to return Gilad Shalit, an Israeli soldier held by Hamas, with Cairo's help.
Olmert is also weak at home due to a corruption scandal that may force him from office. The affair has cracked his coalition government, whose junior partner, the Labour party, pledged to back an opposition bill on Wednesday for dissolving parliament.
Though the legislation to hold early elections would require further ratification to take effect, Israeli media said members of Olmert's Kadima party were trying to coax Labour's leader, Defence Minister Ehud Barak, into withdrawing support. Olmert has also threatened to fire Labour should it vote against him.
Political crises in Israel have, in the past, been deferred to allow the national leadership to deal with major developments in matters of war or peace.
Apart from monitoring Gaza, the Olmert government last month announced the launch of Turkish-mediated talks with Syria. It has also been negotiating indirectly with Lebanon's Hezbollah to retrieve two soldiers the guerrilla group abducted in 2006.
Karnit Goldwasser, the wife of one of the captives, told Israeli television Olmert told her he would ask his cabinet on Sunday to vote for a prisoner exchange with Hezbollah. Cabinet approval would mean the deal would take place within days.
Olmert's office had no immediate comment. Israeli security sources have said that in exchange for the soldiers -- whose condition is not publicly known -- the Olmert government agreed to free five jailed Lebanese guerrillas.
The prospect of the Gaza truce collapsing was alarming for the international Quartet of peace brokers -- chiefly the United States, which wants Olmert and Abbas to cobble together a peace accord before President George W. Bush steps down in January.
In a statement issued after its principals met in Berlin alongside a donors conference where new funds were promised for Abbas's security forces, the Quartet "urged that the calm be respected in full and expressed the hope that it would endure, and lead to improved security for Palestinians and Israelis alike, and a return to normal civilian life in Gaza".
As well as suspending hostilities between Israel and Hamas, the ceasefire, which began last Thursday, required that Israel ease its economic embargo on the impoverished coastal strip.
Israel wants the opening of Gaza's key border with Egypt to be conditioned on a deal for Shalit's release, and Olmert aides said he received assurances on the issue during talks with Egyptian President Hosni Mubarak at a Red Sea resort on Tuesday.
Mubarak said Cairo was "exerting efforts for Shalit" but that he did not want the soldier linked to the Gaza truce.
Hamas leader Khaled Meshaal said last week Shalit's release depended on Israel freeing jailed Palestinians, though the Olmert government has balked at many of the names on the list.
The raid on the West Bank city of Nablus, which killed a Hamas member as well as an Islamic Jihad leader, was the first fatal Israeli action since the truce took hold in Gaza. Similar West Bank operations and Palestinian rocket attacks from the Gaza Strip led to the breakdown of previous truce deals.
Earlier on Tuesday, the Israeli army said Palestinians fired a mortar shell into Israel from Gaza overnight in the first reported violation by militants of the ceasefire. No one was hurt in that incident and there was no claim of responsibility.
In Berlin, Arab League Secretary-General Amr Moussa called for the West to drop its opposition to Abbas reconciling with Hamas a year after the Islamists routed the Palestinian president's forces to take over Gaza.
U.S. Secretary of State Condoleeza Rice rebuffed him.
"You cannot have peace if there is not a partner who respects the right of the other partner to exist," she said, in an apparent reference to Hamas, which Washington refuses to deal with because it does not recognise Israel or past peace accords.
(Additional reporting by Nidal al-Mughrabi in Gaza, Atef Saad in Nablus; Ari Rabinovitch and Will Rasmussen in Sharm el-Sheikh; Adam Entous and Brenda Gazzar in Jerusalem; and Susan Cornwell and Kerstin Gehmlick in Berlin; Editing by Diana Abdallah)