A rebel fighter and a child cross a damaged bridge in Syria's Deir Ezzor on Monday. US President Barack Obama launched an intense lobbying effort on Sunday to sway skeptical lawmakers weighing up whether to support a military strike against Syria. Photo: AFP

A US aircraft carrier is heading closer to Syria, as President Obama labors in seeking the support of Congress over the limited military strike against the Syrian government.

The USS Nimitz aircraft carrier, together with its strike group, is moving west from the Indian Ocean toward the Red Sea, ABC News reported Monday.

It comes after the US Navy has already deployed five destroyers in the Mediterranean for possible missile strikes on Syria.

Syria has been celebrating the delay of an imminent US-led strike after US President Barack Obama said over the weekend that he would consult Congress first. The US then announced they found evidence of the use of sarin gas by the Syrian government in a recent attack on rebel forces.

The Chinese government confirmed Monday that the US has explained to China its evidence relating to the use of chemical weapons in Syria.

"China is firmly opposed to the use of chemical weapons," said Foreign Ministry spokesman Hong Lei at a regular press briefing, adding that China is seriously concerned about any unilateral military action against Syria.

"Any actions taken by the international community should avoid further complicating the Syria issue and avoid bringing more disaster to the Middle East," Hong said.

Obama and his top aides launched a full-scale political offensive on Sunday to persuade a skeptical Congress to approve a military strike against Syria, but faced a struggle to win over lawmakers from both parties and a war-weary American public.

Russian authorities are planning to send a parliamentary delegation to the US for talks with Congress over Syria, in a move publicly endorsed Monday by President Vladimir Putin.

The latest Kremlin initiative appears aimed at persuading the US Congress to vote down Obama's request, although it is unclear what sway the Russian delegates could have over US lawmakers.

Li Haidong, a professor with the Institute of International Relations at China Foreign Affairs University, told the Global Times that the US has been actively prepared for the military strike against Syria, though Obama has postponed the strike time.

"Giving up the military strike would bring a negative impact on Obama's credibility and US global influence, which might make the strike unavoidable," said Li, predicting that the strike might be launched in mid or late September.

Li Guofu, director of the Center for Middle East Studies at the China Institute of International Studies, told the Global Times that the US has encountered setbacks on seeking a wide military coalition and it is trying to win the support of more allies.

France is expected to hand to lawmakers a set of clear evidence that the Syrian government was behind a devastating chemical attack, as French President Francois Hollande is under pressure for parliament to vote on potential military action in Syria.

The Syrian representative in the UN on Monday asked the UN secretary general Ban Ki-moon to "assume his responsibilities and to make efforts to prevent any aggression against Syria, according to the SANA news agency report.

Assad on Sunday said that Syria is "capable of facing up to any external aggression."

Damascus' old city, a tourist site and recreational area, was crowded on Sunday night, partly due to the relief at the US delaying a potential strike.

Repeated heavy shelling in the suburbs of Damascus could be heard from downtown areas. Several rounds of shelling resumed around noon on Monday.

Overseeing the capital from the hilltop of Gasyon, Damascus was shrouded by a layer of black smoke as a result of fights between government forces and rebels scattered on the outskirts of the city.

Russia meanwhile said it remained totally unconvinced that the Assad regime carried out the attack, warning that Western military action would sink efforts to organize a peace conference in Geneva aimed at finding a political solution to the conflict.

Russia is sending a reconnaissance ship to the eastern Mediterranean, Interfax news agency reported on Monday.

Agencies contributed to this story