UNITED NATIONS: The man expected to replace Kofi Annan as the UN-Arab League mediator on Syria, Lakhdar Brahimi of Algeria, yesterday urged world leaders to overcome their differences on a 17-month-old conflict that is descending deeper into full-scale civil war.

"The UN Security Council and regional states must unite to ensure that a political transition can take place as soon as possible," Brahimi said in a statement published on the website of The Elders, an independent group of global leaders committed to peace and human rights.

"Millions of Syrians are clamouring for peace," Brahimi said. "World leaders cannot remain divided any longer, over and above their cries."

It is Brahimi's first public statement on Syria since diplomats said on Thursday that UN Secretary-General Ban Ki-moon was expected to name the veteran Algerian diplomat as early as next week to replace Annan.

Annan, a former UN secretary-general and Nobel Peace Prize laureate, said he would step down on August 31 because he was not able to carry out his job with the UN Security Council's veto powers hopelessly divided and deadlocked.

There are no signs that Brahimi will get his wish anytime soon, if at all. The divisions on the Security Council - above all the split between the US and Russia - run deep.

Russia and China have vetoed three resolutions criticising and threatening sanctions against Damascus for its 17-month attempt to use military force and heavy arms to crush an increasingly militant opposition.

Brahimi, 78, has served as a UN special envoy in a series of challenging circumstances, including in Iraq after the US invasion; in Afghanistan both before and after the end of Taliban rule and in South Africa as it emerged from the apartheid era.