Terror attacks don't appear to be linked

The United States has condemned "heinous attacks" in France, Kuwait and Tunisia but said it had seen no evidence that they were directly coordinated.

"Our thoughts and prayers are with the victims of these heinous attacks, their loved ones, and the people of all three countries," the White House said on Friday.

"We stand with these nations as they respond to attacks on their soil today and we have been in contact with appropriate counterparts in all three countries to offer any necessary support."

Aides said US President Barack Obama was being regularly briefed on the trio of Ramadan-time attacks, which spanned three continents.

"I want to make clear I think there is a common thread here of extremist activity," State Department spokesman John Kirby said.

"But I don't believe we've seen any evidence of tactical coordination ... between the attacks, or by any one or any number of individual terrorist organisations."

In France, a man was beheaded at an American-owned gas factory in the southeast of the country.

A gunman opened fire at tourists visiting a Tunisian beach resort, leaving at least 37 people dead, including foreigners.

In Kuwait City, a suicide bomber blew himself up during prayers at a Shi'ite mosque killing more than two dozen people, in an attack claimed by the Islamic State group.