BEIRUT: Lebanon believes Saad al-Hariri, who resigned as prime minister on Saturday while in Saudi Arabia, is being held by Riyadh, and Beirut plans to work with foreign states to secure his return, a top Lebanese government official said on Thursday.

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

Hariri?s shock resignation, read out on television from Saudi Arabia, pitched Lebanon into a deep political crisis and pushed the country back to the forefront of a regional struggle between Saudi Arabia and Iran.