US President Barack Obama and Hollande spoke by telephone before Obama's statement that he would seek authorization from Congress before any strike.

"The president reaffirmed to him his determination to act to sanction the Syrian government," a source close to Hollande said. "Each country's pace of action must above all be respected. It's important for the Americans to have the green light from Congress."

However, pressure was now mounting on Hollande to also seek formal approval from parliament, which is due to hold a non-voting debate on Syria on September 4.

"Like the US president, who decided to consult the Congress in the name of democratic principles, the French president must organize, after the debate, a formal vote in parliament," Jean-Louis Borloo, the head of French opposition party UDI, said in a statement.

A BVA poll on Saturday showed most French people did not want France to take part in military action on Syria and most did not trust Hollande to do so.

The US president seeks congressional approval for an attack on Syria – meaning that if an attack is launched it will take place only after the Congress returns from recess on September 9 and states its support.

The US and its allies has accused the Syrian government of using chemical weapons against its own people near the capital, Damascus but Syria has vehemently ruled out any involvement in the false flag operation by the foreign-backed militants fighting against the Syrian army.

Syria has been gripped by deadly unrest since 2011. According to reports, the Western powers and their regional allies -- especially Qatar, Saudi Arabia, and Turkey -- are supporting the militants operating inside Syria.

According to the United Nations, more than 100,000 people have been killed and a total of 7.8 million of others displaced due to the violence.

NTJ/SHI