The head of Lebanon's militant group Hezbollah says the country's prime minister, Saad Hariri, was forced by Saudi Arabia to resign.

Hezbollah Secretary General Hassan Nasrallah in a speech Sunday urged patience after Hariri resigned suddenly in a televised address from the Gulf kingdom a day earlier.

Nasrallah accused Saudi Arabia of drafting Hariri's resignation letter and forcing him to read it on Saudi TV. He even asked whether Hariri is being held against his will.

Nasrallah's broadsides against Saudi Arabia have only grown harsher as the rivalry deepens between the Gulf kingdom and Iran over wars in Syria and Yemen. Hezbollah, which has sent thousands of its men to fight in Syria, is supplied and financed by Iran and seen as its proxy in Lebanon.