Fire engulfed a liquor store at a Frederick, Md. shopping center Monday just moments after a gunman barricaded inside had begun negotiating with police.

The fire quickly engulfed the building and sent dark clouds of smoke billowing over the western Maryland city. The location of the gunman was unknown, Frederick police Lt. Thomas Chase said.

The gunman entered Jim's liquor store in the Antietam Village Shopping Center shortly before 1 p.m. and ordered a clerk in the store to leave, Chase said. The clerk ran to a neighboring store and called police. When officers arrived moments later, they were fired upon but not injured.

Frederick police had contacted the man by phone and had begun negotiating with him when the fire started about 3 p.m. and spread to neighboring stores, Chase said. The other stores in the mall were evacuated and no one was injured.