Turkish Prime Minister Tayyip Erdogan accused the UN Security Council on Tuesday, April 3 of indirectly supporting the "oppression" of the Syrian people by failing to adopt a united stance on Syria, Reuters reported.

Once a friend of Damascus, Turkey has become a fierce critic of President Bashar al-Assad over his year-long crackdown on his opponents and has called for the Syrian leader to step down.

"In not taking a decision, the UN Security Council has indirectly supported the oppression. To stand by with your hands and arms tied while the Syrian people are dying every day is to support the oppression," Erdogan said.

In February, the Turkish prime minister described a veto by permanent Security Council members China and Russia of a UN resolution on Syria as a "fiasco for the civilized world".

Russia and China have vetoed two council resolutions condemning Assad for turning his army on civilians. "We will not turn our backs on the Syrian people, we will not leave the Syrian people to their own fate," Erdogan told a meeting of his ruling AK Party on Tuesday.

On Monday UN-Arab League peace envoy Kofi Annan told the 15-nation Security Council that Damascus had agreed to an April 10 deadline to withdraw all military units from towns to pave the way for a ceasefire with rebels two days later.

But Annan also told the council there had been no reduction in violence so far and Western envoys have expressed skepticism about Damascus' intent to halt its assault on opponents.

Assad has repeatedly promised to stop his campaign against anti-government activists, which has brought the country to the brink of civil war, but the fighting has continued.

On Tuesday, Annan's spokesman said an advance team from the UN peacekeeping department was expected in Damascus within 48 hours to discuss deployment of observers to monitor a ceasefire in Syria.