(Adds Islamic Jihad comment) GAZA, Jan 17 (Reuters) - Hamas said on Saturday that it would fight on despite Israel's declaration of a unilateral ceasefire in the Gaza Strip. "A unilateral ceasefire does not mean ending the (Israeli) aggression and ending the siege. These constitute acts of war and so this will not mean an end to resistance," Hamas spokesman Fawzi Barhoum told Reuters in Gaza. He also criticised Israel for taking a unilateral approach rather than entering into a deal with Egyptian mediators: "It is an attempt to pre-empt the Egyptian efforts and any other efforts that seek to achieve a withdrawal of the occupying forces, an end to the siege and a ceasefire." Hamas wants Israel to lift a blockade on trade with Gaza and to withdraw the troops which entered the territory on Jan. 3. Israel said it would cease fire from 2 a.m. (0000 GMT) on Sunday. A rocket from Gaza hit the city of Beersheba around 11 p.m. on Saturday, shortly after Israeli Prime Minister Ehud Olmert announced the planned ceasefire. Other Palestinian militant groups in the Gaza Strip, which like Hamas have fired rockets on Israel, rejected Israel's ceasefire. Olmert said that after the ceasefire Israeli troops will remain in the territory but end "offensive activity". Islamic Jihad said in a statement that "the resistance will continue its battle as long as occupation forces are on the land of Gaza and as long as the siege and the blockade continue." Abu Youssef Said, a spokesman for the Popular Resistance Committees, said: "A unilateral ceasefire is nothing to do with us ... and we will continue to bear arms." He noted that Israel had failed to stop Gaza militants firing rockets and had not secured the release of the Israeli soldier seized in 2006 by Hamas and its allies. Hamas's representative in Lebanon, Osama Hamdan, told Al Jazeera: "If the Israeli military continues its existence in the Gaza Strip, that is a wide door for the resistance against the occupation forces."
Israeli Prime Minister Ehud Olmert (L) shakes hands with Defence Minister Ehud Barak after making statements at the end of Israel's security cabinet meeting in Tel Aviv January 17, 2009. Israel ...