New York - United Nations Secretary General Ban Ki-moon leaves Tuesday on a week-long trip to the Middle East to seek a permanent truce to the fighting in the Gaza Strip.

He goes backed by UN Security Council Resolution 1860, adopted Thursday, which demands an "immediate, durable and fully respected ceasefire."

The fighting in Gaza has intensified despite the resolution, which was adopted by a 14-0 vote. The United States abstained. The US is Israel's strongest ally and its abstention in the ceasefire vote has somewhat weakened the UN's resolve to end the conflict.

US President George W Bush, in a parting press conference Monday before leaving the White House, said Israel "has the right to defend herself."

Ban's bold trip to the Middle East is made difficult by the fact that neither Israel nor Hamas intends to stop the fighting. No US administration in the past six decades has been able to end the Middle East conflict.

"We have a Security Council resolution demanding an immediate and enduring ceasefire. In the name of humanity and international law, this resolution must be observed," Ban told a press conference at UN headquarters.

He will first fly to Cairo to attend talks being sponsored by the Egyptian government to work out a ceasefire. After Cairo, Ban will visit Amman, Jerusalem, an unspecified place in the Palestinian territories, Ankara, Beirut, Damascus and Kuwait City.

"At each stop, I will repeat my call for an immediate and durable ceasefire and insist that UN Security Council Resolution 1860 be respected fully," Ban said. "This means an immediate end to military operations in Gaza, an end to Israel's offensive and a halt to the rocket attacks by Hamas."

The international community must come together to stop the smuggling of weapons into Gaza, he said, adding that other demands include reopening of crossings into Gaza and protection of Gaza residents.

The UN has denounced the excessive use of force by Israel as well as Hamas' firing of rockets and mortars into Israel. The Palestinian toll on day 17 of Israel's Gaza offensive was 905 killed and 4,100 injured. Thirteen Israelis have been killed and dozens injured.

Ban is expected to urge Arab government leaders, particularly the Egyptians, to work harder to ensure that Israel and Hamas end their hostilities. But Hamas has already rejected an Egyptian peace plan, which is strongly supported by the US and UN.

The US abstention in the ceasefire vote has drawn fire from one of America's hawks, former UN ambassador John Bolton.

US Secretary of State Condoleezza Rice, who negotiated in favour of the ceasefire resolution, abstained to the surprise of many delegations.

"Rice's abstention last Thursday neither mitigated the UN Security Council's pressure on Israel, nor increased the likelihood of a ceasefire," Bolton wrote Monday in the Wall Street Journal. "As a display of weakness, it simply invites a diplomatic feeding frenzy."

Bolton said Rice had planned to vote in favour of Resolution 1860, but received new instructions at the last minute not to support it, adding that was "certainly" from Bush.

Bolton, who in the past clashed with Bush over his policies on the Middle East and North Korea, said the US had relinquished its leadership in the Middle East. "An abstention invariably reflects that it (US) failed to achieve its objectives. It also signals timidity."

In past years, the US vetoed without fail any resolutions that criticized only Israel in the Israeli-Palestinian conflict.

Resolution 1860, the result of three days of intense negotiations between the US, France and Britain on the one hand, and Arab governments on the other "condemned all violence and hostilities directed against civilians and all acts of terrorism."

Rice explained her vote, saying it would help Egypt's ceasefire mediation and further US goals in the Middle East.

Israel, Hamas and some Arab governments have sent delegations to Cairo over the weekend to attend discussions on the ceasefire.

Former British prime minister Tony Blair, a special envoy for the Middle East diplomatic "quartet" - the UN, the European Union, the US and Russia - for Palestinian humanitarian issues, said Monday after meeting with Egypt's President Hosny Mubarak that the elements of a ceasefire agreement are being negotiated.

The Carnegie Endowment for International Peace said Mubarak has a lot at stake in the Gaza conflict and now wants a ceasefire without either increasing Egypt's responsibility or allowing Hamas to rearm.

Egypt certainly doesn't want hundreds of thousands of Palestinian refugees in its territory. Mubarak has so far rejected calls to open the Rafah crossing between Gaza and Egypt in order to prevent an influx of Palestinians and the smuggling of weapons and ammunition into Gaza. (dpa)