JERUSALEM, May 15 (Reuters) - Israel is pushing for changes to a stalled U.S. timeline calling for Israel and the Palestinians to take specific steps to bolster the prospects for peacemaking, officials close to the talks said.

The U.S. timeline had asked Israel to take several steps no later than Tuesday, from allowing the Rafah border crossing between Gaza and Egypt to operate five days a week to loosening restrictions on Palestinian travel in the Jordan Valley.

But Prime Minister Ehud Olmert´s office and the Foreign Ministry said the Israeli government has yet to complete a review of the U.S. timeline.

"The (U.S.) timetable was a suggestion and once the proposal becomes something more concrete, then the timetable will be adjusted accordingly," said Olmert spokeswoman Miri Eisin.

Another senior Israeli official said: "Dates can be changed. It´s a blueprint for negotiations."

The U.S. timeline was delivered to Olmert and Palestinian President Mahmoud Abbas late last month as a guide for talks they agreed to hold every two weeks. Those talks have been delayed and the next session is not expected to take place until next week, if then.

Israel´s main objections to the U.S. timeline have centred on two of the 27 so-called "benchmarks" asked of Olmert: the removal of checkpoints around the West Bank city of Nablus by June 15 and the establishment of a bus convoy service between Gaza and the West Bank on July 1.

Israeli officials cited security concerns, and Bush administration officials said the dates in the document did not constitute deadlines.

Israeli officials said some of the steps in the timeline have already been taken and others are nearing completion.

Abbas has favoured the U.S. timeline, though aides said he too would seek to make some amendments.

"We say here that we remain committed to the American security plan," Abbas said in a speech on Tuesday.

The timeline calls on Abbas to deploy his forces to prevent rocket attacks against Israel. In line with the U.S. document, Abbas´s forces recently seized two tunnels used by smugglers along Gaza´s border with Egypt.

Washington hoped these measures would improve conditions for peace talks between Olmert and Abbas, but major hurdles remain.

Olmert is deeply unpopular in Israel and could be forced out of office over his handling of last year´s war in Lebanon.

Abbas could face fierce opposition from the ruling Hamas group if he pushed ahead with the U.S. plan.

At least 11 Palestinians were killed on Tuesday -- eight in one incident -- in the deadliest fighting between Hamas and Fatah since the rivals formed a unity government to end bloodshed threatening to spill into civil war. (© Reuters 2007. 05/15/07)