In the wake of the disaster at the World Trade Center, AT&T Wireless Group reported losing access to some network sites based near or at the Manhattan office complex Tuesday. AT&T Corp., AT&T Wireless, and Sprint Corp. said an inundation of calls was taxing their networks, although calls still were going through.

To assist with recovery efforts, AT&T Wireless has deployed 1,300 wireless phones to federal and local law enforcement and rescue organizations such as the Red Cross, Federal Aviation Administration, airlines, and FBI to assist in immediate communications needs.

The loss of some network equipment that was housed at the World Trade Center has forced Sprint to reroute some calls to other facilities.

Sprint sustained damage to its wireline system because of the equipment loss, according to the company.

"We had some network equipment in one of the twin towers and obviously, it was destroyed," said Mark Bonavia, spokesman for Sprint, in Kansas City, Mo.

The damage forced the carrier to reroute calls to other facilities, and has caused some call "blockages," in which callers were receiving fast busy signals, Bonavia said.

Basking Ridge, N.J.-based AT&T said in a statement it had suffered no damage to long-distance networks as a result of the terrorist attacks.

Instead, AT&T attributed disruptions to high call volumes and suggested calls not be placed to New York or WashingtonAT&T Wireless reported experiencing one of its heaviest call volume days ever, but the network overall is functioning. The company did have a small handful of sites down in Manhattan that were in or nearby the Trade Center.

Additionally, the company is requesting that customers and employees avoid making nonessential calls into and out of critical areas on the East Coast so that more circuits are available for emergency use.

"We're asking customers and employees to try to refrain from using their wireless [phones] unless it's urgent," said AT&T Wireless spokeswoman Danielle Perry, in Paramus, N.J.

To further improve coverage in the city, AT&T Wireless is rerouting traffic and redirecting some of its antennas. For example, the company is deploying "COWS," or Cells On Wheels (essentially cell towers that are mobile and can be moved from place to place for such an emergency), in Jersey City and Brooklyn (east and west of Manhattan) to help improve call capacity.