Armed clashes broke out on Monday evening in Libya’s capital, Tripoli, after reports emerged that a senior militia leader had been killed, prompting a call for de-escalation from the United Nations.

Libyan officials say clashes between heavily armed militias rocked the Libyan capital, with gunfire and explosions heard across the city following the killing of a powerful warlord

The United Nations mission in Libya called for de-escalation Monday after fighting erupted in the North African nation’s capital.