The internationally recognized Libyan government called Tuesday for a civil disobedience campaign in Tripoli until its forces retake the capital from militias who seized it.

Prime Minister Abdullah al-Thani's cabinet said on its Facebook page that it has ordered Libya's armed forces "to advance on Tripoli to liberate it and state institutions from the grip of armed groups".

Nine people were killed Sunday in new violence in Benghazi where pro-government forces have launched an offensive against Islamist militias, raising the toll to 75 dead in five days, medics said.

In the latest violence a woman was killed in a bomb attack that targeted the vacant house of former general Khalifa Haftar, the commander of the offensive launched Wednesday, a military source said.

The United States joined Britain, France, Germany and Italy on Saturday in calling for an "immediate" end to long-running violence there between government forces and militias.

The countries also said in a joint statement that they were ready to use individual sanctions against hostile actors who "threaten the peace, stability or security of Libya or obstruct or undermine the political process."

Libya's internationally-recognized prime minister said Saturday that military forces in the strife-torn country had united to try to recapture Tripoli and the second city Benghazi from Islamist militias.

Abdullah al-Thani also expressed his frustration over a lack of support from the international community, calling for foreign weapons and assistance in the fight against the Islamists.  

Tunisian Prime Minister Mongi Hamdi on Saturday urged Libya to locate two Tunisian journalists who went missing in the neighboring violence-hit country after their arrest by an armed group.

Investigative journalist Sofiene Chourabi and photographer Nadhir Ktari disappeared on September 8 in the eastern Libyan region of Ajdabiya.

The United Nations has urged rival militias in western Libya to observe a truce for at least four days from Saturday to facilitate humanitarian aid for civilians trapped by the fighting.

The clashes first broke out last weekend in when nationalist militia from the hill town of Zintan attacked the twin towns of Kekla and al-Kalaa, which support the Islamist-led Fajr Libya militia.

At least 18 people were killed in fierce clashes Friday between Islamist groups and forces loyal to the army and an ex-general in Libya's second city of Benghazi, hospital sources said.

Benghazi Medical Center said the dead were mostly soldiers and civilians fighting alongside the army in the central district of Al-Majouri.

Islamist militias held their ground Thursday in the face of an assault by an ex-general backed by army units aimed at retaking Libya's second city of Benghazi, military sources said.

Medics said at least 17 people were killed in 24 hours of fighting since Khalifa Haftar's forces early on Wednesday launched what he called an operation to "liberate" the city.

Egyptian warplanes are bombing positions of Islamist militias in the eastern Libyan city of Benghazi, two Egyptian government officials told The Associated Press on Wednesday.

The officials, who have first-hand knowledge of the operation, spoke to the AP on condition of anonymity because they were not authorized to speak to the media.

The Libyan army said it now backs forces loyal to a former general who launched a new bid Wednesday to recapture second city Benghazi from Islamist militias.

"The Libyan army claims 'Operation Dignity'" as one of its own campaigns, spokesman Colonel Ahmed al-Mesmari said, adding, "now it is one operation of the army, among others."