Protestors take part in a rally in front of the White House in Washington D.C., the United States, on Sept. 7, 2013, urging Congress to reject President Barack Obama's plan of military action against Syria. (Xinhua/Wang Fengfeng)

The US Sunday continued to seek Europe's backing for military strikes in Syria as Secretary of State John Kerry visited Paris and London before returning to Washington on Monday.

The diplomatic lobbying came as the Obama administration is making efforts to rally support at home in a crucial week for the US to launch the strikes.

The US and France Saturday claimed growing international support for the action after EU nations called for a strong response to Syria.

The bloc did not explicitly back the military action, but Kerry said he was "encouraged" by the "very powerful statement" made, adding that there were "a number of countries, in the double digits, who are prepared to take military action."

Dong Manyuan, a deputy director of the China Institute of International Studies, told the Global Times that these countries could just participate in a very general sense. "Providing intelligence and services could also be counted as taking part in a military action."

The US Congress is scheduled to return from its summer break on Monday to consider Obama's plans for strikes. On Saturday, a US congressional panel posted graphic videos of what senators were told were Syrian victims of the August attack, many of them children.

Obama warned of the dangers of turning "a blind eye" to chemical attacks in his weekly address after returning from the G20 summit in Russia that remained deadlocked over the Syria crisis.

Some 200 protesters gathered outside the White House Saturday before marching to Capitol Hill, in a demonstration opposing possible strikes against Syria.

Zhang Guoqing, a research fellow of the Institute of American Studies at the Chinese Academy of Social Sciences, said that seeking approval was the result of a compromise between the Obama administration and the congress.

"The congress wants more power in launching the action," said Zhang, adding that Obama doesn't want to upset the congress as negotiations over the annual budget are imminent.

UN inspectors are expected to release a report into an alleged chemical weapons attack this weekend. However, Kerry said Obama had made no decision about whether to wait for the report's release.

"The strikes are estimated to last about one or two days, which aim to balance the power between the government and rebels," said Dong, adding that the rebels are waiting for a sign for the attacks and preparing to turn the tables on the regime.

Fighting continued to rage inside Syria, with the Syrian Observatory for Human Rights reporting Sunday that rebel forces had taken control of the historic Christian town of Maalula, north of Damascus.

AFP contributed to this story