WASHINGTON?A District of Columbia postal worker is ?gravely ill? with inhaled anthrax, leading government officials to order testing for as many as 2,300 more mail employees, Mayor Anthony Williams said Sunday.

The man, whose identity was not disclosed, was in serious condition at a suburban Virginia hospital.

The third person to come down with the most serious form of the disease, he checked into the hospital Friday and was diagnosed Sunday morning, said Dr. Ivan Walks, the city?s chief health officer.

?He is acutely ill,? said Janice Moore, a spokeswoman for Inova Fairfax Hospital.

Beginning Sunday, more than 2,100 employees at the city?s main mail processing center and an additional 150 at an air mail handling center near Baltimore-Washington International Airport will be tested for exposure to anthrax spores and receive treatment, the mayor said.

?We?re going to do everything we can and everything we have to do,? he said.