CAIRO — The United Nations chief expressed horror at the discovery of at least eight mass graves in Libya in recent days and called for a prompt and transparent investigation into possible war crimes.
The graves were uncovered after fighters loyal to Khalifa Hifter, whose 14-month campaign to capture Tripoli collapsed in recent weeks, retreated from Tarhuna, 40 miles southeast of the capital.
The mass graves were a grim reminder of the atrocities on all sides of Libya’s chaotic war, a conflict fed by foreign powers seeking strategic advantage or a share of the country’s vast energy reserves, but which is led by lawless Libyan militias that behave with impunity.
Since he launched himself into the war in 2014, Mr. Hifter, who is backed by Russia, Egypt and the United Arab Emirates, has sought to present himself as the leader of a disciplined, national military force. But his troops have faced accusations of serious crimes.
U.N. Secretary-General Antonio Guterres said he was “deeply shocked” by the discovery and he called on the Tripoli government to secure the graves, identify victims, establish causes of death and return the bodies to their next of kin.
Pictures circulating on social media showed bodies heaped in the ground, tangled in plastic, or buried in pits in the desert outside Tarhuna. Separately, government officials found dozens of bodies in the town morgue, as well as stacked inside a shipping container.
Investigators in plastic suits began the work of cataloging the decomposing bodies, and said they would use DNA samples to assist with identification.
As they retreated from the front lines around Tripoli in recent weeks, Mr. Hifter’s fighters and allied Russian mercenaries left behind explosive devices in suburban homes. Photos circulating on social media showed bombs tied to children’s toys, and munitions with Russian markings.
Tarhuna was Mr. Hifter’s final stronghold in western Libya, and after it fell last week the government’s Turkish-backed forces initially faced accusations of human rights abuses.
Government troops looted stores, burned buildings and carried out revenge killings against supporters of al-Kaniyat, the Hifter-allied militia that had fled Tarhuna days earlier. At least 16,000 people in Tarhuna and southern Tripoli were forced to flee their homes, the United Nations said.
Then the focus turned on Mr. Hifter’s side, with the discovery of mass graves.
The interior minister, Fathi Bashagha, said Friday that dozens of bodies had been found in at least eight graves. Some victims appeared to have been buried alive.
Separately, investigators found a shipping container filled with charred bodies, possibly of detainees.
Mr. Bashagha accused al-Kaniyat of “heinous crimes.” The militia has long had a reputation for harsh treatment of perceived dissenters.
It is unclear when the killings took place.
In August 2018, al-Kaniyat allied with a faction from the town of Misurata, now on the government side, to mount a brief assault on Tripoli. In April 2019, al-Kaniyat switched sides and joined Mr. Hifter in his assault on Tripoli.
Rights monitors said it was vital that international investigators are allowed immediate access to Tarhuna to determine how and when the people in the mass graves died.
David Schenker, a senior State Department official, told reporters Thursday that he was “troubled” by the discovery of the graves, as well as by the reports of land mines and other explosive devices left behind by Mr. Hifter’s forces.
American officials have become notably more outspoken in their criticism of Mr. Hifter in recent weeks, ever since Russia stepped up its involvement in the war by sending at least 14 warplanes to defend Mr. Hifter’s retreating troops, according to the Pentagon.
Mr. Hifter’s hasty retreat from Tripoli has sent Libya’s war in a new and unpredictable direction.
In recent days, the fighting has shifting to the central city of Surt, the birthplace of former dictator Col. Muammar el-Qaddafi, where Turkish-backed government troops are facing off against Mr. Hifter’s Russian-supported forces. Thousands of civilians in the area have fled their homes.
Turkish warships have circled in the Mediterranean close to Surt, and on Friday conducted exercises in conjunction with fighters jets in an apparent show of strength. Russian cargo planes landed at a large airport just south of the city. It is unclear if they were carrying supplies or people into the city, or out of it.
Egypt is spearheading a diplomatic drive to bring Mr. Hifter into political talks that would shore up his position in eastern Libya and an area known as the “oil crescent,” where most of Libya’s oil is produced, and which he still controls.
On Friday, Egypt’s president, Abdel Fattah el-Sisi discussed the Libya crisis with the President of France, Emmanuel Macron, also an ally of Mr. Hifter, the Egyptian presidency said in a statement. They agreed to support Mr. Sisi’s political initiative, the statement said, and to continue backing Mr. Hifter’s forces “in combating terrorist and armed groups.”