PM Hariri accuses Hizballah of causing Lebanese political deadlock
At a press conference in Beirut on Tuesday, Saad Hariri said "it's Hizballah, full stop", when asked who was blocking the formation of a government.
He said the Shia paramilitary group bears full responsibility for the consequences, including Lebanon's flagging economy.
Hariri stopped short of resigning, however, saying there was still an opportunity to bridge the differences.
Hizballah wants six allied Sunni legislators to be represented in the new cabinet, a demand rejected by Hariri, Lebanon's top Sunni leader.
Lebanon held its first parliamentary elections in nine years in May.
On 24 May, after parliamentary elections, President Michel Aoun quickly nominated Saad Hariri for his third term as prime minister and tasked him with forming a cabinet.
Key parties have jostled over ministries since the vote, with officials and foreign donors warning that a delay would aggravate the country's economic troubles.
Lebanon is no stranger to drawn-out negotiations over forming governments, but the current delays risk squandering a precious $11 billion package of economic aid.
The last government has continued as a caretaker administration since that election, which produced a parliament tilted in favour of the Iran-backed Hizballah movement.
Lebanon is governed by a complex system which aims to maintain a precarious balance of power across religious and political communities.
Its major political players have always ruled through consensus, which leaves little to chance, and typically includes dizzying horse-trading, with negotiations often dragging out.
In 2009, Hariri needed five months to pull together his first government, and it took Tamam Salam double that time to announce his in 2014.