Four soldiers were killed on Thursday in and around Libya's violence-wracked eastern city of Benghazi, the cradle of the revolution that toppled dictator Moamer Kadhafi in 2011.
And in the south, an explosion killed at least 10 people and wounded many more at an arms depot in an incident thought to be crime-related.
The Benghazi fighting came on the final day of a three-day strike in protest over militias, sparked by a Monday shootout between jihadists and the army that left seven people dead and 50 wounded.
In the day's worst single incident, three soldiers were killed in a firefight with unidentified gunmen on the city's eastern outskirts.
"Three soldiers were killed and three wounded soldiers were admitted to the hospital," Al-Jala hospital spokeswoman Fadia al-Barghathi said.
A security source said the fighting erupted east of the city.
"These victims fell in clashes in the Sidi Khalifa district between the army and an armed group that was trying to enter the city from the east," the source said, adding that the group's allegiance was unknown.
Earlier on Thursday, witnesses said gunmen inside the city killed a soldier on the final day of the three-day protest strike.
That attack was carried out by gunmen in a vehicle who sprayed a volley of bullets at two soldiers as they got into a car after leaving a cafe, witnesses said.
"The soldier died after being shot in the head," said a medic at Al-Jala hospital.
Witnesses said the second soldier escaped unharmed.
Thursday's killings in Benghazi come a day after three soldiers were shot dead, and the bodies of two more found, in the nearby town of Derna, an Islamist stronghold.
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Benghazi city council declared the three-day strike after an army patrol was attacked near the headquarters of Ansar al-Sharia, a jihadist group blamed for a 2012 attack on the US consulate in which the ambassador and three other Americans were killed.
On Wednesday, UN officials said the world body is to send a 235-strong special force to Libya to protect UN staff.
Libya has seen mounting unrest since Kadhafi was toppled by a ragtag assortment of rebel brigades, many of which have since been transformed into militias that defy the weak central government.
The UN force, probably to be taken from peacekeeping missions, would guard the UN base in the capital Tripoli.
"This would act as a deterrent against extremist elements who are not welcoming of foreign personnel," UN chief Ban Ki-moon commented.
In another sign of the security problems plaguing the North African nation, at least 10 people were killed and 15 wounded in a blast at a weapons depot in the south on Thursday.
An official said that the incident may have been linked to common theft.
"A group of unknown people tried to attack the depot, causing this unfortunate incident" in Brak al-Shati, 650 kilometres (400 miles) south of Tripoli, General Mohamed al-Dhabi told AFP.
State television reported that a group of civilians, among them African immigrants, had been trying to steal ammunition in order to remove valuable copper when the explosion occurred.
The broadcaster did not give a precise toll, saying only that an unspecified number of people had been killed and wounded.
On Sunday during a visit to London, US Secretary of State John Kerry vowed to work with the international community to try to restore order in Libya.
Rebels helped topple and kill Kadhafi in 2011, but have since banded into militias carving their own fiefdoms, each with its own ideology and regional allegiance.