Prime Minister Saad Hariri's resignation, in a surprise move following a trip to Saudi Arabia, has brought down the coalition government and thrusts Lebanon into the front line of a regional competition between Saudi Arabia and Iran.

Hariri announced his resignation, citing Iran's
Hariri announced his resignation, citing Iran's "grip" on the country and threats to his life. (AP)

Lebanon's prime minister Saad Hariri resigned on Saturday, saying in a televised broadcast from an undisclosed location he sensed a plot to target his life and criticising Iran and the Lebanon's Hezbollah.

"We are living in a climate similar to the atmosphere that prevailed before the assassination of (his father, the late prime minister) martyr Rafik al Hariri. I have sensed what is being plotted covertly to target my life," he said.

Hariri said Iran was "losing in its interference in the affairs of the Arab world", adding that Lebanon would "rise as it had done in the past" and "cut off the hands that wickedly extend into it".

In comments directed at Iran, he said the Arab world would "cut off the hands that wickedly extend to it".

Hariri, who is closely allied with Saudi Arabia, alleged in a broadcast from an undisclosed location that Hezbollah was "directing weapons" at Yemenis, Syrians and Lebanese.

Saudi Arabia's Gulf Affairs Minister Thamer al Sabhan said the personal security detail of Hariri, who resigned on Saturday, had "confirmed information" of a plot to kill him.

Speaking in an interview on Future, an Arabic television channel owned by Hariri, he said Hariri was in Riyadh, adding there were "security threats to the prime minister and the kingdom is keen on his safety". 

Hariri became Lebanon's prime minister late last year after a political deal that also brought Hezbollah ally Michel Aoun to office as the country's president.

Hezbollah is politically dominant in Lebanon, but its ties to Iran and its support for Syrian President Bashar al Assad have angered some Lebanese.

Hariri has visited Saudi Arabia, a political foe of Iran and Hezbollah, twice in the past week, meeting Crown Prince Mohammed bin Salman and other senior officials.

Beirut-based Al Jadeed television reported Hariri's resignation statement was made and broadcast from the Saudi capital Riyadh.

Reactions to Hariri's resignation

A member of Hezbollah's central committee, Sheikh Nabil Kawouk, accused Riyadh of being behind Hariri's resignation, saying in a speech reported by Al Jadeed : "God protect Lebanon from the evil of Saudi Arabia's reckless adventures."

Walid Jumblatt, the leader of Lebanon's Druze minority, said Lebanon was too weak to bear the consequences of Hariri's resignation, saying he feared political and economic fallout.

"We cannot afford to fight the Iranians from Lebanon," he said, advocating an approach of compromise with Hezbollah in Lebanon while waiting for regional circumstances to allow Saudi-Iranian dialogue.

Iran's Foreign Ministry said Hariri's departure was a plot to "create tension in Lebanon and the region".

"Hariri's resignation was done with planning by Donald Trump, the president of America, and Mohammed bin Salman, the crown prince of Saudi Arabia," said Hussein Sheikh al Islam, adviser to Iran's supreme leader.

Source: TRTWorld and agencies