The names of the 23 New York Police Department officers who lost their lives at the World Trade Center were unveiled on a memorial wall during a ceremony Monday.

To the sound of bagpipes playing "Amazing Grace," the names were unveiled at Battery Park City on the huge granite wall as Gov. George Pataki, Mayor Michael Bloomberg, Police Commissioner Raymond Kelly and families and friends of the deceased officers looked on.

Two NYPD officers who died in 2000 in the line of duty also were added to the wall.

The officers killed "will never be simply a list of names. They will be remembered as officers who performed heroically on the darkest day that our city has ever seen," said Bloomberg. The wall "will help keep their memory alive."

Pataki said that the officers' families were "still missing them so much, getting used to the reality without them."

The ceremony opened with the "Star Spangled Banner," sung by a uniformed police officer.

The New York City Police Memorial Wall honors every officer who has died in the line of duty in the department's history. Thirty-seven Port Authority of New York and New Jersey police officers also died Sept. 11.

In 2001, the only NYPD officers killed in the line of duty were the 23 who lost their lives at the World Trade Center. That was more lives lost than in any other year in the NYPD's history.

The police department retired the officers' badge numbers, which were emblazoned beside their names. Families were called up to the podium one by one during the ceremony to receive replicas of the badges.

The World Trade Center victims' names were separated from the other 580 fallen officers listed at the memorial.