Vice President Dick Cheney (search) agreed not to attend the city's ceremony at the World Trade Center site Thursday after Mayor Michael Bloomberg (search) said he was concerned the extra security would inconvenience relatives of the victims.

Instead, Bloomberg said he asked Cheney to attend a memorial service later in the day for the 84 employees of the Port Authority (search) of New York and New Jersey who were killed during the trade center attack. The agency is the owner of the trade center property.

Bloomberg, a Republican, said the vice president's security needs at the trade center site likely would have included special credentials and bag searches and it would have taken hours to grant access to relatives of the 2,792 victims.

"It was intrusive on the families, and first and foremost, this event downtown at this site has to be for the families. They are coming to visit where their loved ones died," he said Wednesday.

Cheney's office said that the vice president would attend the afternoon Port Authority service. He is not scheduled to speak.

"The vice president is going to the ceremony to show the administration's respect and reverence to the people of New York," said his spokeswoman, Cathie Martin.

"The last thing we want to do is be disruptive of any remembrance ceremony that is occurring," said White House press secretary Scott McClellan.

During the first anniversary of the attack last year, President Bush did not attend the main ceremony, but did visit the trade center site a few hours later. That evening, the president addressed the nation from Ellis Island.

This year, Bush will observe a moment of silence on the South Lawn at 8:46 a.m., the time the first plane hit the trade center, and will attend a prayer service. Later in the day, he will meet troops wounded in Iraq.