France persuaded US president Donald Trump to stay in Syria and launch air strikes as punishment for an alleged chemical weapons attack, French president Emmanuel Macron has said.

Appearing live on French television BFM and online investigative site Mediapart, the 40-year-old leader said the US, Britain and France had “full international legitimacy to intervene” with the strikes, to enforce international humanitarian law.

The allies fired missiles early on Saturday at three chemical weapons facilities in Syria to punish the regime for the alleged attack on the town of Douma.

Debris surround the Syrian Scientific Research Centre which was attacked by US, British and French military strikes (Hassan Ammar/AP)
Debris surround the Syrian Scientific Research Centre which was hit by US, British and French military strikes (Hassan Ammar/AP)

“It was retaliation, not an act of war,” Macron said in justifying the operation a day before the French parliament was set to debate it.

“Ten days ago president Trump wanted the United States of America to withdraw from Syria. We convinced him to remain,” he said.

He said France now wanted to involve Western powers, Russia and Turkey in a new diplomatic initiative to find a sustainable political solution in Syria.

Macron also offered to play the role of intermediary between the United States and Russia, whose relationship has been on edge over the chemical weapons attack and amid allegations that Russia tried to interfere in the US 2016 presidential election.

The French leader will make a state visit to the US next week and is scheduled to travel to Russia next month.