"Since the armed conflict in Tripoli, Libya began, 432 people have died, 2,069 people have been wounded, and more than 50,000 have had to flee their homes," WHO tweeted.
"Every day of violence means more people killed, injured, or displaced," WHO added.
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.
During a cabinet meeting last Thursday, Libyan Prime Minister Fayez Serraj said there will be no cease-fire until the rival army forces "return to where they came from."
Libya has been struggling to make a democratic transition amid chaos since the fall of former leader Muammar Gaddafi in 2011.