At least 10 people were shot dead in Libya's capital, reports said as the UN mission in the war-scarred country on Monday called for a "prompt and thorough" investigation.
Some Libyan media reported that more than a dozen people died in the shootings on Saturday in a villa in Tripoli's Abu Salim district, without pointing to who was behind the killings.
The incident happened on the 13th anniversary of the popular revolt that ended Moamer Kadhafi's 42-year dictatorship, which sparked years of war and turmoil in the north African country.
The UN Support Mission in Libya said on social media platform X that it "condemns the violent incident in Abu Salim area, Tripoli on 17 February during which at least 10 people were reported killed," and that it continued to monitor the situation.
Abu Salim is under the control of strongman Abdel Ghani al-Kikli, head of the Stability Support Authority (SSA) created in January 2021.
The SSA said on Sunday on Facebook that two of its members were among those killed.
UNSMIL said the incident "highlights concerns repeatedly raised" by its head Abdoulaye Bathily "about the serious risks posed by rivalries between security actors that continue to threaten the fragile security in Tripoli".
It said it "urges relevant Libyan authorities to ensure an independent, prompt and thorough investigation into the incident and prevent any actions that could lead to escalation and further violence."
The director of security in Tripoli announced on Sunday the opening of a criminal investigation into the deaths.
Libya has been gripped by political chaos and insecurity since the fall of Kadhafi in 2011 in a revolution backed by NATO.