The first day of the Pittsburgh Home & Garden Show closed down two hours earlier than planned this evening because of a bomb threat.

Show visitors and exhibitors at the David L. Lawrence Convention Center, Downtown, were told to evacuate the building about 8 p.m. after someone called in a bomb threat, authorities said.

"We thought it would be prudent to make sure people were out of the building," said John DeSantis, executive director of the Pittsburgh Home & Garden Show.

Police brought in bomb-sniffing dogs and were going through the building tonight as a precaution. The show, which runs through Sunday, Mar. 16, is scheduled to open its doors on time tomorrow at 10 a.m.

Visitors were told to leave the building over the convention center's public address system.

"He warned it was not a test. It was serious and everyone should evacuate," said Greg Reynolds, an exhibitor who has a roofing and chimney business in Uniontown.

The show features about 1,500 exhibitors and is one of the biggest shows of the year at the convention center.