Syrian peace talks were due to resume in Geneva on Tuesday with the warring sides deadlocked over the explosive issue of transferring power from President Bashar al-Assad's regime.

UN mediator Lakhdar Brahimi admitted as the talks closed on Monday that the negotiations "haven't produced much." But he said he would bring the country's warring sides together again Tuesday for another attempt at discussions.

Monday marked the third day of UN-sponsored talks between the two sides in Geneva and the first dealing with political issues.

The two sides have been brought together in the biggest diplomatic push yet to end a civil war that has left more than 130,000 dead.

Monday's session broke up quickly after the regime set out a statement of principles that did not deal with a political transition and was immediately rejected by the opposition.

Officials on both sides said they had no plans to leave the talks however.

The opposition says Assad must leave power and a transitional government formed based on the agreement reached during a first peace conference in Geneva in 2012.

The regime says Assad's role is not up for debate at the Geneva II talks, and denies that the initial Geneva deal requires him to go.

Also on Monday the Cape Ray, a specially-equipped US naval ship left for Italy on a ground-breaking mission to destroy Syria's most dangerous chemical agents, Pentagon officials said.

The ship is due to arrive in the southern port of Gioia Tauro in about "two to three weeks," spokesman Colonel Steven Warren said.

US Defense Secretary Chuck Hagel sent a letter to Captain Rick Jordan and the 135-member crew telling them they were embarking on a "historic mission."

Chinese foreign ministry spokesperson Hua Chunying said Tuesday that the Chinese frigate Yancheng had re-entered Syrian waters as part of the second mission to transport chemical weapons, in close cooperation with Russian, Danish and Norwegian vessels. The mission is being executed rapidly and safely, she said.

Syria's entire chemical arsenal is to be eliminated by June 30.

AFP