Authorities say the Libyan capital, which has been under attack by commander Khalifa Hifter's forces since last month, has seen its water supplies resume two days after gunmen shut the pipes down, depriving over 2 million residents of water.

The Interior Ministry says the gunmen on Sunday stormed the offices of a water distribution agency that runs a network of underground pipelines providing the capital and the region with water, and shut it at gunpoint.

The ministry says the gunmen demanded Tripoli release their leader Khalifa Ahnish's brother, jailed for belonging to an outlawed group.

The U.N. humanitarian coordinator, Maria Ribeiro, condemned the attack and said that such actions "may be considered war crimes."

The water distribution agency says water supplies to Tripoli resumed on Tuesday, without elaborating.