Syria strike brings rare criticism for Trump from France's Le Pen

US President Donald Trump's decision to order a missile strike on Syria brought rare criticism on Friday from French far-right leader Marine Le Pen, who has until now viewed the American leader as an ideological soulmate.

The US strike reverberated through the French presidential election campaign, just two weeks before the first round of voting, with most leading candidates taking a cautious, or a critical, stance towards the US action.

"I am a little surprised because Trump had said repeatedly that he didn't intend the United States to be the world's policeman any longer and that is exactly what he did yesterday," Le Pen told France 2 television.

The United States fired cruise missiles at a Syrian airbase on Friday as punishment for a suspected chemical weapons attack on Tuesday which killed at least 70 people.

"Is it too much to ask to wait for the results of an independent international investigation (into Tuesday's attack) before carrying out this kind of strike?" Le Pen asked.

She said she didn't want a repeat of events in Iraq and Libya where she said Western intervention had "brought chaos and ended up strengthening ... terrorist organisations."