Hariri not being held against his will: French minister

Lebanon's Saad Hariri, who resigned as prime minister at the weekend, is "free to move around", French Foreign Minister Jean-Yves Le Drian said on Friday amid rumours he was being held against his will in Saudi Arabia.

"He went to Abu Dhabi the day before the President (Emmanuel) Macron's visit (on Wednesday) so we think he's free to move around," Le Drian told Europe 1 radio, adding: "It is up to him to make his choices."

Lebanese Foreign Minister Gebran Bassil on Thursday demanded the return of Hariri from Saudi Arabia, where he announced his plans to step down in a shock decision on Saturday.

In his televised speech, Hariri said he was stepping down because of Iran's "grip" on Lebanon and threats to his life, but the comments led to immediate speculation about Saudi pressure.

Al-Akhbar newspaper, which is close to Iranian-backed movement Hizballah, suggested that Hariri, who holds Saudi nationality, was being held "hostage" in Riyadh.

Macron made a surprise overnight trip to Saudi Arabia on Thursday-Friday during a Middle East tour that saw him attend the inauguration of the new Louvre museum in Abu Dhabi on Wednesday.

"The Lebanese situation is the most worrying subject of the moment," Le Drian added in his interview on Friday morning.

Lebanon "was moving towards a new solution with a new constitution, elections to come. The departure of Prime Minister Hariri creates new uncertainties," Le Drian said.

Meanwhie the US declined to comment on the issue. State Department spokeswoman Heather Nauert told a press briefing on Thursday that Chris Henzel, the US charge d'affaires in Riyadh, met Hariri on Wednesday, but refused to say where the meeting took place or to clarify Hariri's status.

"[The talks] were sensitive, private, diplomatic conversations," Nauert said.

"We have seen him. In terms of the conditions of him being held or the conversations between Saudi Arabia and Prime Minister Hariri, I would have to refer you to the government of Saudi Arabia and also to Mr Hariri's office."

Also on Thursday, Russia's ambassador to Lebanon, Alexander Zasypkin, threatened to refer Hariri's case to the UN Security Council if the "ambiguity" continues.

Hariri's announcement raised fears that Lebanon - split into rival camps led by Hariri and Hizballah - could once again descend into violence.

His resignation came amid an intensifying proxy war between Saudi Arabia and regional arch rival Tehran who have long vied for influence in Lebanon.

The Sunni leader had been sharing power with the Shia militant movement Hizballah in hard-won national unity government, but the arrangement had come under increasing fire from Saudi Arabia.