President Donald Trump warned Iran on Wednesday of a “heavy price” if it or its allies in Iraq attack US troops stationed there.

“If this happens, Iran will pay a very heavy price, indeed!” Trump tweeted.

The US president also wrote: “Upon information and belief, Iran or its proxies are planning a sneak attack on U.S. troops and/or assets in Iraq.”

It was not clear whether Trump meant Washington actually has the intelligence of such a plan.