Reports say as many as 140 people, including civilians, may have died in an attack on an airbase in Libya.
It was originally thought 60 people died when a government-allied militia tried to take over the Brak al-Shati base on Thursday.
The UN-backed government’s defence minister and the commander of the militia have both been suspended pending an investigation.
The prime minister’s office has denied ordering the attack.
Most of the dead were soldiers of the self-proclaimed Libyan National Army, an alliance in the east of the country which does not recognise the government in the capital, Tripoli.
The UN’s envoy to Libya, Martin Kobler, said he was outraged by reports of executions.