The mosque and shrine of al-Shaab al-Dahmani, sacred to Sufi Muslims in Libya, was damaged Saturday with bulldozers. A witness in Tripoli told the BBC that authorities had no reaction to the razing.
Sufis accuse ultra-conservative Salafi Muslims for the attack, which came a day after a shooting attack on a 15th-century Sufi sacred tomb 100 miles southeast of Tripoli in Zlitan.
Independent experts working for the United Nations said similar attacks were reported last October and continued for much of this year.
"These events amount to the violation of numerous human rights provisions," a U.N. statement read. "The attacks on Sufi religious sites require a swift and rigorous response by the authorities, without which they are likely to continue and spread."
The panel expressed concern that Libyan authorities did little to stop the demolition of the al-Shaab mosque.
Heiner Bielefeldt, U.N. special envoy on religious freedom, said such incidents are considered acts of aggression against members of a certain faith.
"The long-term prospects for freedom of religion or belief and religious diversity in the entire country seem to be at stake," he said in a statement.