Rescue and recovery workers plan to gather at the National September 11th Memorial in Downtown Manhattan on May 30 to mark the 10th anniversary of the official end of the cleanup at the World Trade Center site.

Mayor Michael Bloomberg said the event will honor the sacrifices made by first responders, but warned spots for the event are limited.

Some first responders objected when only family members of victims were allowed to attend the 10th anniversary observances of the September 11th terror attacks.