Lebanon believes Saad al-Hariri is being held in Saudi Arabia, from where he resigned as Lebanese prime minister, two top government officials in Beirut said, amid a deepening crisis pushing Lebanon onto the front lines of a power struggle between Saudi Arabia and Iran.

A third source, a senior politician close to Saudi-allied Hariri, said Saudi Arabia had ordered him to resign and put him under house arrest. A fourth source familiar with the situation said Saudi Arabia was controlling and limiting his movement.

In a televised statement indicating deep concern at Hariri's situation, his Future Movement political party said his return home was necessary to uphold the Lebanese system, describing him as the prime minister and a national leader.