Violent clashes in the ethnically-divided west Chinese region of Xinjiang have left 21 people dead, including police officers and social workers, a local official said Wednesday.

Gun fights broke out Tuesday in Bachu county when officials searched homes of locals suspected of possessing weapons, the Xinjiang government propaganda office said.

The 15 killed in the “violent attacks” were either police or social workers, with 11 of them being members of China’s Uighur ethnic minority, who live mainly in the region. Six “gang members” were shot dead in the clashes, it added, while eight were captured alive.

The report described the clashes as “an act of terrorism”, according to AFP.

The death toll from Tuesday’s violence was the highest the region has seen in months following sporadic clashes amid tensions between ethnic Muslim Uighurs and Han Chinese communities.