Homeland Security Secretary Michael Chertoff (search) said Thursday that 1,400 National Guard troops per day are being sent to New Orleans to control looting and lawlessness, quadrupling its regular police force by the weekend.

Already, 2,800 National Guardsmen are in the city to help local police since Hurricane Katrina (search) produced devastating floods in New Orleans, Chertoff said at a news conference with Attorney General Alberto Gonzales (search). Another 1,400 Guard troops and military police units are being added daily, he said.

"Security is a concern," Gonzales said. "It is a priority."

National Guard troops are controlled by the governors of individual states.

"We will be deploying into New Orleans a force the size of the New Orleans (search) police department each day, every day, for the next three days. That is a remarkable movement of law enforcement capability into an area that clearly needs augmentation and reinforcement," Assistant Defense Secretary Paul McHale said.

Separately, Chertoff said the Coast Guard has rescued 3,000 people from flood and hurricane-damaged areas but acknowledged that continued flooding in New Orleans has made the federal government's job unusually difficult.

Local law enforcement has rescued thousands more.

"We continue to search 24/7. We search by day. We search by night," Chertoff said.

"As long as there is someone on roof waving a flag, we're gong to be sending a helicopter out there to get them," the secretary said.

Chertoff noted that pictures of New Orleans have shown that looting continues. The additional enforcement presence is meant to "send an unambiguous message that we will not tolerate lawlessness or violence" that interferes with the relief effort," he said.

Chertoff said evacuation efforts from New Orleans' Superdome have been complicated by a continued influx of new refugees there. He said authorities hope to clear the stadium in 24 hours, although it could take longer.