Shelling by Yemen's Shiite Houthi rebels in the heavily contested western city of Taiz struck a museum housing rare manuscripts and the possessions of a deceased ruler, activists said Wednesday.

Activist Reham al-Badr, who inspected the National Museum in Taiz, told The Associated Press that Shiite rebels have routinely shelled the district where it is located, which is defended by local fighters.

She said the museum was struck Sunday.

The interior walls of the building were torched black and the museum was filled with rubble and twisted metal.

Al-Badr, who visited the museum earlier Wednesday, said it housed a collection of watches, guns, swords, gifts from foreign visitors and manuscripts belonging to Imam Ahmed, who ruled until the 1960s.

Houthi spokesmen declined to comment.

Yemen has been torn apart by conflict since 2014, when the rebels allied with troops loyal to a former president and captured large swaths of the country, including the capital, Sanaa.

Taiz, Yemen's third-largest city, lies along a main route from the port city of Aden, held by a loose array of forces allied with the internationally recognized government, to Sanaa.

Residents and aid groups say the Houthis have been indiscriminately shelling Taiz and blocking the delivery of humanitarian aid.

A Saudi-led coalition launched an air campaign against the rebels in March 2015. Since then, more than 5,800 people have been killed. More than 80 percent of Yemenis are in dire need of food, water and other aid, according to the United Nations.

Several historic monuments across Yemen have suffered damage since the start of the conflict, according to the U.N. The Ottoman-era al-Owrdhi historical compound, outside the walls of Sanaa's old city, was severely damaged last June.

ABC News