TRIPOLI, May 8 (Xinhua) -- The UN Support Mission in Libya (UNSMIL) on Wednesday expressed concern over increasing abductions, arbitrary detentions and disappearances in the capital Tripoli, as the fighting between the east-based army and the UN-backed government continues in and around the city.

"UNSMIL is deeply concerned about increasing cases ... inflicted upon officials, activists and journalists. These cases warn of deterioration of the rule of law in Libya," the mission said in a statement.

UNSMIL demanded all Libyan conflict parties to "adhere to human rights and rule of law obligations. All authorities must ensure that arrests and detentions fully comply with "due process and fundamental fairness."

"At least seven officials and employees were arbitrarily detained or kidnapped in Libya. The fate of them remains unknown, and there may be others who have disappeared under similar circumstances," UNSMIL revealed.

It also urged all Libyan parties to immediately release those arbitrarily arrested and detained, and not to engage in such crimes.

"The taking of hostages during a conflict is a violation of International Humanitarian Law and may amount to a war crime," the mission warmed.

The east-based army, led by Khalifa Haftar, has been leading a military campaign since early April to take over Tripoli, where the UN-backed government is based.

The fighting so far has killed 443 people, injured 2,110 others, and displaced nearly 60,000 others, according to the World Health Organization.

Libya has been struggling to undergo a transitional period amid chaos since the fall of former leader Muammar Gaddafi in 2011.