At least 12 people were killed in a blast at an explosives and ammunition factory in the Karesi district of Balikesir province in northwest Turkey on Tuesday, the country’s interior ministry said.

At least four others were injured in the explosion, which also caused a building to collapse, according to the ministry.

Turkish President Recep Tayyip Erdogan said on X that he was “deeply saddened by the death of 12 of our brothers.”

“I pray to God to have mercy on my deceased brothers, offer my condolences to their families, and wish a speedy recovery to our injured,” Erdogan added. “My condolences to Balikesir and our nation.”

Turkish Justice Minister Yilmaz Tunc said on X that a committee of experts, including chemical, mechanical, occupational safety and geophysical engineers, had been assigned to determine the cause of the explosion.

This is a developing story and will be updated.