The European Union is calling for a ceasefire in Libya, warning that the conflict around the capital Tripoli is a threat to international peace and security.

The self-styled Libyan National Army, led by Field Marshal Khalifa Hifter, launched an offensive on Tripoli last month. The LNA, based in eastern Libya, is battling rival militias loosely allied with the U.N.-supported government in the capital.

In a statement Monday, EU foreign ministers called "on all parties to immediately implement a ceasefire and to engage with the United Nations to ensure a full and comprehensive cessation of hostilities."

They underline that "indiscriminate attacks on densely populated residential areas may amount to war crimes" and say those responsible should be held to account.

Tripoli-based government head Fayez Sarraj met with the ministers Monday.