Several schools were locked down Monday as SWAT teams searched downtown Manchester for a gunman who critically wounded a police officer in an early morning shooting.

Heavily armed SWAT teams searched a 40-block area with help from a police helicopter and canine units. Officers searched vehicles leaving the neighborhood.

"They are doing a yard-to-yard search," police Capt. Richard Tracy said.

Few details about the shooting, near an intersection, were released.

Robert Tarr, who lives about a block away, said he and his wife heard shooting around 3 a.m., followed by yelling. "We heard six loud bangs go off," he said.

Other neighborhood residents reported hearing seven, eight or even 10 shots.

Police referred calls for comment to the attorney general's office, which didn't return phone messages.

The schools locked down included Central High, Hillside Middle School and several elementary schools, assistant school Superintendent Karen Burkush said. She said entrances to some other schools were locked and being monitored.

Tarr, a member of a neighborhood watch group working with police to combat prostitution and drug dealing, said things had been getting better.

"Now we're back to square one again," he said.