Analysts said hope for a political resolution to the Syrian crisis remains despite Kofi Annan's resignation on Thursday as the UN-Arab League Joint Special Envoy for Syria.

The former UN secretary-general announced on Thursday his decision to quit at the end of the month, saying "the increasing militarization on the ground (in Syria) and the clear lack of unity in the Security Council have fundamentally changed the circumstances for the effective exercise" of his role.

China expressed regret over Annan's resignation, Foreign Ministry spokesman Hong Lei said in a statement.

China remains open to any proposal that can help politically solve the Syrian issue and supports the United Nations role in achieving the resolution, Hong said.

Li Baodong, China's permanent representative to the UN, also voiced support for Annan's meditation efforts and the full implementation of his six-point plan at Security Council meetings.

Annan's six-point peace plan to promote a peaceful solution to the Syrian crisis is endorsed by the Security Council, but violence has intensified in some parts of the country.

UN military observers earlier confirmed that Syrian opposition groups are using heavy weapons in their fight against the government.

The resignation symbolizes the deep divisions in the international community over a crisis that UN officials now said has claimed more than 20,000 lives, said the Christian Science Monitor.

Annan said that the bloodshed in Syria continues "most of all because of the Syrian government's intransigence and continuing refusal to implement the six-point plan and also because of the escalating military campaign of the opposition".

Syria's Foreign Ministry reiterated the country's commitment to Annan's peace plan, stressing the leadership's belief in national dialogue as the sole way to resolve the current crisis without any foreign intervention.

The possibility of a political resolution still remains since Damascus still controls the general situation, which has been acknowledged by some opposition parties, said An Huihou, former Chinese ambassador to Egypt, Tunisia, Lebanon and Algeria.

After Annan's resignation, officials from Russia, the United States, the European Union and Britain also expressed continued commitment to the peace plan.

"Although the possibility of inclusive political dialogue has diminished, the West's support for the plan still leaves hope for a peaceful resolution to the Syrian crisis," said Qu Xing, head of the China Institute of International Studies.

"However, differences over details in the peace plan exist among the related parties," Qu added. "The West still wants the removal of Syrian President Bashar al-Assad as a precondition for political dialogue, while China insists the future of Syria should be decided by Syrians."

UN Secretary-General Ban Ki-moon on Thursday said he was consulting with the League of Arab States about the "prompt appointment of a successor (to Annan) who can carry on this crucial peacemaking effort".

According to an ABC news report, John Bolton, former US ambassador to the UN, does not share Ban's optimism, saying that the position no longer has a role to play and would not be a career-enhancing move for anyone.

It is not easy to find another envoy as qualified as Annan, said An. "But the final resolution of the Syrian issue doesn't depend on the choice of envoy, but on joint efforts from international community, including the West changing its biased position toward Syria."

Contact the writers at zhaoshengnan@chinadaily.com.cn and yuweizhang@chinadailyusa.com

Xinhua and Reuters contributed to this story.