Libyan Prime Minister Ali Zeidan vowed Tuesday to stay at his post, and Islamist ministers later quit his government in protest at persistent lawlessness that saw him briefly abducted last year.
Zeidan accused the Justice and Construction Party -- the political arm of the Libyan branch of the Muslim Brotherhood that has been bloodily repressed in neighbouring Egypt since the ouster of elected president Mohamed Morsi -- of seeking to destabilise his government.
The resignation of the five ministers came after three weeks of wrangling over an Islamist-inspired censure motion against the premier.
The Islamists failed to secure the required 120 votes in the 194-member General National Congress to pass the motion. and 99 members signed a petition of protest earlier Tuesday.
But Zeidan, an independent who has the backing of the liberal Alliance of National Forces, remained defiant, telling the private Al-Ahrar television channel he would not step down.
Zeidan has said repeatedly that he will quit only when there is consensus on a successor to avoid a power vacuum in the midst of the mounting insecurity gripping large swathes of the country two and a half years after the overthrow of veteran dictator Moamer Kadhafi.
Earlier this month, the premier said he would soon announce a major cabinet reshuffle, something he promised to do repeatedly last summer without ever taking action.
Zeidan has said his critics in the GNC are a "minority," but said he would "willingly" leave the post of premier if the assembly chose to replace him.
The JCP said it was "withdrawing its ministers from Zeidan's government and holds those in the Congress who backed his government responsible."
Zeidan was "incapable of taking the country where it needs to go," the party said.
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The party has five ministers in Libya's 32-member interim administration -- those for oil, electricity, housing, economy and sport.
Earlier, 99 MPs, including those of the JCP, signed a petition of protest accusing Zeidan of a "crushing failure" in his efforts to assert central government control over former rebel militias that operate with virtual impunity across much of the country.
The prime minister was himself abducted from a Tripoli hotel in October and held for several hours by former rebel militiamen.
Since last summer, security guards at key oil export terminals in the east of the country -- many of them former rebel fighters -- have blockaded exports, delivering a devastating blow to hard currency receipts and government revenues.
The protesters are demanding a restoration of the autonomy the eastern Cyrenaica region enjoyed in the first decade after independence in 1951.
Similar protests among the ethnic Berber minority in the west and among the Toubou in the south have also hit oil and gas exports.
On Saturday, the GNC declared a state of emergency in the south in response to deadly ethnic unrest.
Al-Qaeda inspired groups have taken advantage of the lawlessness to establish a growing presence.
In September 2012, jihadists attacked the US consulate in Libya's second city Benghazi, killing Ambassador Chris Stevens and three other Americans.
Earlier this month, the US State Department put two Libyan groups, both operating under the name Ansar al-Sharia, on its terror blacklist for their alleged role in the attack.