Washington  - US President George W Bush telephoned Israeli Prime Minister Ehud Olmert on Wednesday for an update on the fighting in the Gaza Strip and to explore ways to end the conflict.

The White House has said that Bush will support a ceasefire only if Hamas militants stop firing rockets into Israel.

"President Bush thinks that Hamas needs to stop firing rockets, and that is what will be the first steps in a ceasefire," Gordon Johndroe, a White House spokesman, said in Crawford, Texas, where Bush is vacationing.

The death toll continued to climb on Wednesday as Israel's air campaign in the Gaza Strip entered its fifth day. More than 390 Palestinians in the densely populated Strip have died since fighting erupted.

Hamas continued with rocket barrages into Israel. Israel launched the military campaign in response to rocket attacks and has vowed to not only halt the attacks, but to devastate Hamas so that it cannot carry out future attacks. Four Israelis have died.

"Hamas needs to agree, not only to stop firing rockets now, but to not fire any rockets in the future, stop smuggling weapons in so they don't even have the ability to fire rockets," Johndroe said.

Olmert also assured Bush that Israel was taking steps to avoid harm to civilians in Gaza and to allow humanitarian aid into the enclave. (dpa)