Holding loved ones' photographs at the World Trade Center site, more than 150 relatives of Sept. 11 victims urged the city to call in a military unit that specializes in finding and identifying human remains.

The recent discovery of hundreds of body parts in a manhole on the site and in a skyscraper just outside it proves the city didn't do a thorough job, they said in calling for an expanded search.

"We shouldn't have to rally. We shouldn't have to beg," said Robin Audiffred, who has no remains for her husband, James. "You need to make it right. You need to do whatever it takes at this point."

Mayor Michael Bloomberg said the unit, called the Joint POW/MIA Accounting Command, wouldn't be brought in, although the city plans to hire up to 10 more forensic experts.

"We have the expertise in house," Bloomberg said. "This is an investigation where, when you have the expertise, you really want to do it locally. It's the city's responsibility."

Some 200 pieces of bone and other remains have been found since utility workers doing routine work on the western edge of the site found remains in an abandoned manhole. Officials have said the manhole had been paved over and forgotten when a service road was built there during excavation of the trade center's rubble.

After the discovery, city officials identified about 10 more manholes and pockets under the road and ordered them to be excavated immediately and sifted for remains.

The work involves tearing up parts of side streets, exploring the rooftops of selected buildings near the 16-acre site and excavating more manholes beyond the dozen the city is already exploring.

Crews digging into a dozen manholes along the service road should tear it up because more remains could be beneath it, said Norman Siegel, a lawyer for the families. A grass-covered area near ongoing construction of a subway line on the site also needs to be searched, he said.

Deputy Mayor Edward Skyler, who is overseeing a renewed search for remains, has said that area will be examined.

Two high-ranking officials involved in recovery work after the attacks told The Associated Press that the area in question was on one end of a road that carried equipment into the site.

Steel from the trade center had pierced a retaining wall at that spot, making it impossible to completely dig up the area around it by the time the recovery process ended, said the officials, who spoke on condition of anonymity because they were not authorized to speak about the recovery process.

Searches at ground zero continued Thursday. Although no new victims have been identified from the recent finds, the city medical examiner's office said this week that remains were identified for three more victims after the families submitted additional DNA samples to the medical examiner's lab.

That means 1,601 of the 2,749 victims in New York have been identified, including Karen Martin of Danvers, Mass., a flight attendant on the plane that crashed into the north tower.

Martin's cousin, Michelle Pare, said Thursday news of the recovery was "bittersweet."

"We thought she just disintegrated — her body did — not her memory," said Pare. "Now it's a bigger relief. We really have her."