BEIRUT -- Lebanon's president accused Saudi Arabia on Wednesday of detaining his country's prime minister, calling it an act of "aggression" and asking U.N. Security Council nations and European governments to intervene.

It was the first time Michel Aoun described Prime Minister Saad Hariri as a detainee of the kingdom, after Hariri announced his resignation under mysterious circumstances from Riyadh 12 days ago.

Iranian President Hassan Rouhani meanwhile ratcheted up the rhetoric against Saudi Arabia, his country's main regional rival, saying the kingdom pressured Hariri to resign in a "rare" intervention in another nation's affairs.

Rouhani also accused Saudi Arabia, without naming the kingdom, of "begging" Israel to bomb Lebanon. Hassan Nasrallah, the leader of Lebanon's Iran-backed militant group Hezbollah, has made the same accusation.

Saudi Arabia has accused Hezbollah of aiding Iran-allied rebels in Yemen, who fired a ballistic missile that was intercepted outside the Saudi capital earlier this month. Hezbollah has said Saudi Arabia forced Hariri to resign in order to bring down his coalition government, which includes the group.

Hariri is a Saudi ally who holds dual citizenship. He announced his unexpected resignation in a pre-recorded statement broadcast on Saudi TV on Nov. 4, in which he lashed out at Hezbollah and said he feared for his safety.

"We consider him detained, arrested" in violation of international laws, Aoun wrote on his official Twitter account. Aoun is a Hezbollah ally but is personally close to Hariri.

Later Wednesday, Aoun said Saudi Arabia had committed a "hostile act against Lebanon," and that he had called the ambassadors of U.N. Security Council nations about the matter. He said Arab mediation to resolve the crisis had failed.

In a quick response to Aoun, Hariri tweeted that he was fine and will return to Lebanon as promised. "You will see," Hariri wrote, without elaborating.

The head of Future TV, affiliated with Hariri's party, said the prime minister is expected back before Sunday, when Arab foreign ministers meet in Cairo in an emergency session at Saudi Arabia's urging. Riyadh is expected to discuss Iran's rising influence in the region, as well as the Lebanon crisis.

Lebanon's Foreign Minister Gibran Bassil said in Paris that Lebanon wants to resolve Hariri's "ambiguous" condition with Saudi Arabia in a "brotherly" fashion.

But Bassil, who is on a European tour seeking support for his country amid the crisis, said that Lebanon also has the option of resorting to international law, without elaborating. It was not immediately clear if Bassil would attend the Arab League meeting in Cairo.

France's foreign minister is expected in Saudi Arabia on Wednesday to meet with Hariri and Saudi officials. French President Emmanuel Macron paid a surprise visit to the kingdom last week.

Associated Press writer Nasser Karimi in Tehran, Iran, contributed to this report.