TRIPOLI, June 1 (Xinhua) -- At least 17 civilians have been killed and 22 others wounded in the eastern Libyan city of Darna over the past two weeks as the eastern-based army is launching a military operation to take over the city from militants, the United Nations said on Friday.

"The escalation of fighting in Darna has reached unprecedented levels during the past week, with fighting further encroaching into densely populated areas. Since May 16, at least 17 civilians, including two children, have been killed and another 22, including seven children, injured in the conduct of hostilities," the UN Support Mission in Libya (UNSMIL) said in a statement.

"The number of civilian casualties was the highest in the past two days, with seven killed and another seven injured on May 30 in an explosion as they were attempting to leave the city," the statement said.

"Humanitarian access to Darna is extremely limited. Severe food and medicine shortages continue to worsen. Electricity and water are intermittently cut off for the approximately 125,000 residents," the statement added.

The Mission appealed to all parties to the conflict in Darna to "allow unfettered and safe access of humanitarian workers and needed assistance. UNSMIL remains engaged with all parties in an effort to de-escalate the conflict."

The eastern-based army, led by General Khalifa Haftar, has been besieging Darna since 2015, demanding that the Shura Council of the Mujahideen, a coalition of Islamist militias, leave. The army accuses the armed group of being loyal to al-Qaida.

Since the beginning of the fight between the army and the militants, more than 30 soldiers were killed and more than 40 others injured, according to military and medical sources.