Staffan de Mistura, the UN envoy for Syria, has met Syrian President Bashar al-Assad in Damascus, pushing for the implementation of a UN plan including local truces.

A statement from Assad's office following Monday's meeting said the president was ready to study a proposal to "freeze" fighting in the northern city of Aleppo.

"President Assad has been informed by de Mistura of the main points of his initiative," said the statement.

"[Assad] said it was worthy of study and that work on it is needed ... in order to re-establish security in Aleppo."

It is de Mistura's second visit to Syria since he was appointed to his position in July.

On October 30, the Italian-Swedish envoy put forward an "action plan" for Syria that proposed to "freeze" fighting in local areas to allow for aid deliveries, and to lay the groundwork for peace talks.

'Importance of Aleppo'

According to the Syrian presidency's Facebook page, Assad emphasised "the importance of Aleppo," which rebels and the army have been fighting over since July 2012.

Unfortunately many local truces achieved thus far have more closely resembled surrender arrangements, as opposed to genuine, sustainable ceasefire arrangements. Jen Psaki, US State Department spokeswoman

A UN statement said de Mistura "takes note of the expressed intent of the Syrian authorities to work with the United Nations to identify common ground for implementing his proposal on incremental 'freezes', starting with the city of Aleppo".

The city is split into rebel- and army-held areas and the envoy had previously said Aleppo would be a "good candidate" to become a "freeze" zone.

Since December 2013, regime warplanes have carried out near daily air raids targeting rebel-held districts of what was once Syria's economic capital, reportedly killing mostly civilians and defying a UN Security Council ban on such strikes.

The UN said the proposed "freezes" are intended to allow for return to some normalcy for civilians caught in the conflict, and, along with diplomatic efforts, pave the way for a national all-inclusive political process.

The US cast doubt on reports that Assad was ready to implement the UN plan, saying the regime had a poor record sticking to truces.

"We certainly support ceasefires that would provide genuine relief to Syrian civilians and are consistent with humanitarian principles," State Department spokeswoman Jen Psaki said.

But she added that "unfortunately many local truces achieved thus far have more closely resembled surrender arrangements, as opposed to genuine, sustainable ceasefire arrangements".

After meetings with Syrian officials in Damascus, de Mistura travelled to the city of Homs. Pro-regime daily Al-Watan reported that he was going to meet opposition groups and UN personnel stationed in the al-Waer neighbourhood.

During his three-day visit, de Mistura was also scheduled to meet opposition figures tolerated by the government to present his new initiative on halting fighting in specific areas across the country.