Turkish Prime Minister Recep Tayyip Erdogan met Iranian President Mahmoud Ahmadinejad for an unannounced talk on the sidelines of the Democracy Forum in Bali on Thursday, the Turkish daily Hurriyet reported.

The two had not been expected to hold any talks over the course of the conference.

The two leaders began talking on their way to dinner, continuing their conversation at the table, according to the daily. The conversation centered around the crisis in Syria, the report said.

Erdogan earlier this week sharply criticized the UN Security Council for its failure to agree on decisive steps to end the 19-month civil war in Syria.

Recep Tayyip Erdogan told an international conference in Istanbul that the world was witnessing a humanitarian tragedy in Syria.

"If we wait for one or two of the permanent members ... then the future of Syria will be in danger," said Erdogan, according to an official translator.

Russia and China - two of the five permanent members of the Security Council - have vetoed resolutions that sought to put concerted pressure on Damascus to end the conflict and agree to a political transition.

Erdogan called for a reform of the Security Council, which he called an "unequal, unfair system" that didn't represent the will of most countries.