Islamist militias launched an air strike near key oil terminals in eastern Libya on Tuesday, stepping up a battle for the government-held facilities, a security official said.

Vendors briefly blocked the road in the northern port city of Tripoli on Tuesday to protest a decision by the municipality to remove their carts.

The state-run National News Agency reported that the vendors had blocked al-Qobbeh and Majlaya road with burning tires to protest the decision.

The army announced on Monday the arrest of two suspects linked to unrest in the northern region of Bhannine and city of Tripoli in October.

It said that Lebanese Ibrahim Mohammed al-Saghir was detained in the North for belonging to a terrorist group.

Islamist fighters clashed with pro-government forces for the second consecutive day Sunday as they pressed an advance on a key oil region in eastern Libya, sources on both sides reported.

Separately, at least four Fajr Libya militiamen were killed and 10 wounded in an air strike by pro-government forces near the Ras Jedir border crossing with Tunisia, a military source said.

Prominent Salafist leader Dai al-Islam al-Shahhal claimed on Friday that the Lebanese army arrested his son Jaafar in the northern city of Tripoli overnight.

Al-Shahhal said an army intelligence unit apprehended Jaafar in the area of al-Zahriyeh.

Lebanese security forces have arrested a Lebanese man in the North on suspicion of recruiting scores of fighters and sending to Syria via Turkey, pan-Arab daily al-Hayat reported on Monday.

The daily quoted political sources as saying that the man has admitted to contacting several fighters via Twitter and sending them to Turkey through Tripoli's port.

A Lebanese army expert dismantled on Friday a hand grenade and a home-made bomb in the northern city of Tripoli, the military announced.

The grenade and bomb were discovered by an army patrol in a empty water bottle in Tripoli's al-Amercan neighborhood, it said in a communique.

Around 20 Lebanese fighters from the city of Tripoli and other areas in the North have lately traveled to Syria to join the extremist Islamic State group, highly-informed security officials said.

The officials, who were not identified, told As Safir daily that the fighters headed to Syria via Turkey in the past weeks.

The army is cautiously carrying out precautionary measures at the entrances of the southern Ain el-Hilweh Palestinian refugee camp as Salafist cleric Sheikh Ahmed al-Asir denied that he is residing there.

According to Ad Diyar newspaper published on Friday, the Lebanese army fortified its posts in the southern city of Sidon and appointed female soldiers to search veiled women after obtaining reports that Islamist fugitive Shadi Mawlawi and Asir are planning to escape from the Palestinian camp.

Jamal Hayak is finally fixing up his restaurant, damaged a month ago in clashes between the army and militants in this northern Lebanese city. But he has little doubt violence will erupt again, and he says he fears next time it will be Islamic State group fighters battling in Tripoli's streets.

"In the beginning we used to say. 'This is the last time.' Now we've had Round 21 and 22 (of fighting), so we say God knows," said Hayak, 56, grimy with dust as he fixed his shop, shelled during the four days of fighting in late October that killed over 20 people.