The five permanent members of the UN Security Council on Tuesday began a closed-door discussion over a new Syria resolution to end the country's months-long violence.

The new draft resolution, proposed by the United States, demanded "unhindered humanitarian access" and called for efforts from the Syrian government to end violence and withdraw troops from protest-hit cities.

It also asked the Syrian authorities to release all prisoners detained for protests.

Ambassadors from the five major UN powers -- Britain, China, France, Russia and the United States, along with Morocco, the only Arab representative on the 15-nation council, took part in the discussion.

It remained unclear about the details of the draft resolution and outcomes of the discussion.

Syrian President Bashar al-Assad on Tuesday pledged to defend the nation against "foreign plots" and accused Western countries of attempting to undermine the country's stability.

"The Syrian people have foiled all previous foreign schemes and have proven once again that they are able to protect their homeland and build a new Syria though their determination to carry on with the reforms in tandem with confronting the foreign-backed terrorism," Assad said when meeting with a Ukrainian delegation.

The UN discussion was held ahead of the upcoming visit by former UN Secretary-General Kofi Annan, who was appointed by the UN and the Arab League as special envoy to address the crisis in the violence-wracked Syria.

The Syrian government said Monday that it welcomed Annan and sanctioned a visit of UN emergency relief coordinator Valerie Amos for an evaluation of the country's humanitarian situation.

China on Tuesday voiced support for the mediation efforts by Annan, saying China hoped the visits would be "conducive to the political settlement of the Syrian problem."

"China is ready to render humanitarian assistance to the Syrian people," Li Baodong, China's permanent representative to the UN, told the UN-based Chinese media Tuesday night.

Last month, China and Russia vetoed a UN Security Council draft resolution on the Syrian issue, calling for the international community to resolve the country's crisis through dialogues and negotiations.

Also on Tuesday, Li Huaxin, Chinese special envoy to Syria, arrived in Damascus to hold talks with Syrian officials. Li's visit was widely seen as part of China's diplomatic efforts to peacefully solve the Syrian problem.

Li described his visit as "positive and constructive" efforts to find a peaceful solution to the country's violence, which as the UN estimated has claimed more than 7,500 lives since it broke out in March 2011.

On Sunday, the Chinese Foreign Ministry issued a six-point statement, reiterating China's stance that the Syrian issue should be determined by the Syrians themselves.

Earlier this week, Syria suffered a fresh round of sanctions from the United States and Canada.

Canadian Foreign Minister John Baird said his country has completely banned the provision or acquisition of financial or other related services, and taken sanctions on the Syrian central bank and seven high-ranking Syrian officials implicated in the violence.

Meanwhile, the United States slapped economic sanctions on Syria's General Organization of Radio and TV, saying they aided Damascus in its campaign to put down a popular uprising.

Syrian Information Minister Adnan Mahmoud lambasted the U.S. sanctions on Tuesday, describing them as a "hostile" movement.