BENGHAZI, Libya — Islamic hardline militias, including the group accused by the United States in a 2012 attack that killed the ambassador and three other Americans, claimed control of Libya’s second-largest city, Benghazi, after overrunning army barracks and seizing heavy weapons.
The sweep in the eastern city is part of a new backlash by hardliners against their rivals ahead of the sitting of a new Parliament.
In the capital Tripoli, escalating battles Thursday between militias prompted multiple foreign governments to scramble to get out their citizens as thousands of Libyans fled across the border into Tunisia.
The weeks-long surge of violence renewed fears that Libya, which has been in chaos since the 2011 civil war that ousted longtime dictator Moammar Khadafy, is plunging deeper into civil strife.
With a crippled central government and weak army and police, the country’s numerous rival militias have held sway in Libya for the past three years.
Though they battled one another frequently, a balance of fear among them prevented any from going too far and forced them to divide areas of power. But now, militias led by Islamist and extremist commanders appear to be trying to gain a more decisive upper hand.
The Health Ministry said in a statement Thursday that the death toll in Tripoli since the violence intensified in the past month reached 214, with more than 981 people wounded.
Militias allied to Islamist politicians have been fighting for weeks to wrest control of Tripoli’s airport from rival militias, destroying much of the airport in the process.
On Thursday, witnesses said random rocket fire hit houses and vehicles in western Tripoli, sending residents fleeing.
Shelling hit a funeral, killing four children and three women from a single family, security officials said. Thursday evening, thousands of residents marched into Tripoli’s central Martyrs Square in a protest denouncing militias.
Tripoli residents said fuel and gasoline shortages were worsening, and food prices had leaped. ‘‘All of this is caused by political parties that are fighting for power,’’ said Abdelfattah Alghanai, a man shopping for vegetables.
By noon Thursday, more than 10,000 Libyans fled by land across the border into neighboring Tunisia over the previous 12 hours, Tunisia’s state news agency reported.