Free Syrian Army soldiers are seen during clashes with government forces at the south-west district of Salah al-Din in Aleppo, Syria.

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

“The U.N. 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 clamoring 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 told Reuters on Thursday that U.N. Secretary-General Ban Ki-moon was expected to name the veteran Algerian diplomat as early as next week to replace Annan.

Annan, a former U.N. secretary-general and Nobel Peace Prize laureate, said he would step down on Aug. 31 because he was not able to carry out his job with the U.N. 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 United States and Russia - run deep.

Russia, with the aid of China, has vetoed three resolutions criticizing and threatening sanctions against Damascus for its 17-month attempt to use military force and heavy arms to crush an increasingly militant opposition. One senior Western envoy said more than 20,000 people have been killed by Assad's forces.

Washington, U.N. diplomats said, saw little point in replacing Annan since Moscow continues to support Syrian President Bashar al-Assad and opposes sanctions intended to pressure Damascus into halting the violence.

It also believes the deadlocked Security Council cannot play a constructive role in the conflict and intends to bypass it in the future. The administration of U.S. President Barack Obama is instead moving, albeit cautiously, to increase its backing for anti-Assad rebels.

The United States blames Russia for undermining Annan's attempts to secure a ceasefire and implement a six-point peace plan that was embraced by the government and rebels but never implemented.

Moscow, Syria's chief ally and principal arms supplier, blames the United States, Qatar and Saudi Arabia for supporting Syrian rebels, including providing weapons. It also says Washington and its European allies on the Security Council have rejected “reasonable” proposals for resolving the conflict.

Brahimi, 78, has served as a U.N. special envoy in a series of challenging circumstances, including in Iraq after the U.S. invasion that toppled Saddam Hussein; in Afghanistan both before and after the end of Taliban rule, and in South Africa as it emerged from the apartheid era. - Reuters