PARIS (Reuters) - France on Thursday appeared to dismiss claims by Yemeni Houthi rebels that they were behind an attack on Saudi oil facilities, and said Paris would renew efforts to defuse tensions between the U.S. and Iran at next week’s U.N. General Assembly.

French Foreign Minister Jean-Yves Le Drian speaks during a news conference with Egyptian Foreign Minister Sameh Shoukry (not pictured) in Cairo, Egypt September 17, 2019. REUTERS/Mohamed Abd El Ghany

France has been scrambling with its European partners to ease tensions between Washington and Tehran for months, but last weekend’s attack has jeopardized those efforts, diplomats have said.

The Trump administration and Saudi Arabia have pointed the finger at Iran for the Sept. 14 raids, which hit the world’s biggest crude oil processing facility and initially knocked out half of Saudi output.

Yemen’s Iran-aligned Houthi movement has claimed responsibility for the attack. Iran, which supports the Houthi group, has denied any involvement in the attacks.

“The Houthis ... announced that they launched this attack. That lacks credibility,” French foreign minister Jean-Yves Le Drian, told C News television, adding that at this stage Paris would not draw conclusions that Iran was behind it.

“There is an international investigation, let’s wait for its results. I don’t have a specific opinion before these results.”

He said the Saudi investigation would be fast.

France’s Armed Forces Ministry spokeswoman said seven of its experts in explosives, surface-to-air defenses and missile trajectory had been sent to Saudi Arabia to help make an independent assessment of the attack.

France, which has a naval base in neighboring Abu Dhabi, had the Jean Bart warship operating in the area at the time of the attack.

“It is an act of war. When missiles hit another country it is an act of war, but we have to go back to the principle of de-escalation,” Le Drian said.

He said France would continue its efforts to defuse the crisis at next week’s U.N. General Assembly. French President Emmanuel Macron was scheduled to meet Iran’s President Hassan Rouhani and Trump, he said. Iran has said the Iranian leader has yet to receive a visa for the trip.

“Iran must return (fully) to the nuclear deal. It is a requirement. It needs the economic benefits of the accord, but we must also discuss the rest,” Le Drian said, referring to regional security.