A Libyan health official says fighting between rival militias for control of Tripoli has killed at least six civilians.

Malek Merset, a spokesman for the health ministry in Tripoli, says Wednesday that at least 26 people were also wounded in an overnight shelling in the Abu Salim district, less than 7 kilometers (around 4.5 miles), from the city center.

The fighting pits the Libyan National Army, led by Khalifa Hifter and aligned with a rival government in the east, against militias affiliated with Tripoli's U.N.-supported government.

Both sides traded blame for the shelling.

The U.N. said Tuesday that heavy weapons and shelling have damaged houses, schools and civilian infrastructure in and around Tripoli.