Beirut: Lebanese Prime Minister Sa'ad Hariri's bombshell resignation in a televised speech took the nation by surprise on Saturday.
In his announcement, Hariri accused Iran and its Lebanese ally, Hezbollah, of holding Lebanon hostage and destabilising the Arab region.
But what is behind his resignation and what does it mean for Lebanon?
Hariri became prime minister in late 2016 in a coalition government that included the militant group Hezbollah.
It has been an uneasy partnership between Hariri, and Hezbollah, Iran's Shiite proxy in Lebanon, which has sent thousands of its fighters to shore up President Bashar Al Assad's forces in Syria's civil war.
As Hezbollah and Iranian-backed Syrian troops made successive military victories, Hariri came under pressure from Washington and Riyadh to distance himself from the group.
In recent days, Lebanese government ministers have bickered publicly over sending an ambassador to Damascus and repatriation plans for hundreds of thousands of Syrian refugees living in Lebanon. Officials denied the tension threatened the unity government.
It is not clear what exactly prompted his shock resignation - unprecedented in the way it was announced in a televised address. Even close aides seemed not to know it was coming.
In his speech, Hariri said he feared for his life, suggesting he may not be coming home soon. Hariri was prime minister from 2009 until 2011, when Hezbollah ousted him from office. He had until last year lived in self-imposed exile in Saudi Arabia and France.
WHAT HAPPENS NOW
Hariri's resignation has to be accepted by President Michel Aoun, a formality. It effectively shatters the national unity government and plunges the country into uncertainty and potentially a prolonged period of political paralysis.
Aoun must appoint a new prime minister, but it will be difficult to find a consensual Sunni figure able to form another coalition government. According to Lebanon's sectarian-based power-sharing system, the president must be a Maronite Christian, the prime minister a Sunni and the parliament speaker a Shiite.
A new government that leans further toward Hezbollah would risk isolating the country and subjecting it to US sanctions.
Already, Lebanon's Hezbollah has been targeted by US sanctions aimed to block the flow of money to the group, a move that threatened to cause major damage to the country's solid banking sector if passed into law. Washington considers Hezbollah to be a terrorist organisation and US lawmakers called it Iran's leading "terrorist proxy."
With Saudi Arabia and the US seeing eye to eye on the need to stem Iran's growing clout, many fear Lebanon may be the place for a showdown with Iran's ally, Hezbollah.
Israel and Hezbollah have fought a number of wars, the last of which ended in a stalemate in 2006. Israel has recently said it will not tolerate an Iranian presence in Syria, spearheaded by Hezbollah, which has also established a presence near the Syria-Israel border.