UNITED NATIONS: The U.N. human rights chief said all parties in Libya have committed numerous grave human rights abuses ranging from deadly attacks on civilians to executions, abductions and torture.

Zeid Raad al-Hussein said in a report to the U.N. General Assembly circulated Tuesday that Libya is facing the worst political crisis and escalation of violence since longtime dictator Moammar Gadhafi was overthrown in 2011 which has had a devastating effect on human rights.

He said the country is now split between two governments, one that is internationally recognized and another backed by Islamist militias, which both claim legitimacy, "while powerful armed groups exercise effective control on the ground, committing violations of international human rights and humanitarian law with impunity."

Zeid said throughout 2014 the U.N. mission in Libya and his office received reports of targeted assassinations, car bombings and beheadings, with human rights defenders, civil society activists and media professionals as well as members of the judiciary and law enforcement among the victims.

The high commissioner for human rights said they also received reports of civilians being abducted "solely for their actual or suspected tribal, family, political or religious affiliation and nationality."

The U.N. also received reports of tens of cases of children injured or killed as a result of shelling in Tripoli and Benghazi, and in attacks on schools and hospitals. Several women activists reported being threatened with death if they continued promoting women's rights, he said.

Zeid said the justice system continues to be attacked and isn't functioning in Tripoli, Benghazi and other parts of the country.

"There has been no known prosecution of leaders or members of armed groups, despite serious and continuous human rights abuses being carried out," he said. And groups such as councils of elders have sprung up to fill the gaps left by the largely non-functioning courts, "further undermining the rule of law."

Zeid said the prosecution presented its case in June in less than one hour, without calling any witnesses, against 37 people including Gadhafi's son, Seif al-Islam Gadhafi, and his former intelligence chief, Abdullah al-Senoussi, on charges of murder and persecution linked to the violent suppression of the 2011 rebellion.

"If the trial continues to proceed in this way, it will not meet international standards," Zeid warned. "It will also constitute a missed historical opportunity to publicly disclose and scrutinize crimes committed under the former regime."