The head of the agency overseeing development of the World Trade Center site announced Thursday he is stepping down at the end of the month.

John Whitehead, chairman of the Lower Manhattan Development Corp., also is leaving his post as chairman of the World Trade Center Memorial Foundation, but will remain on its board. Thomas Johnson, the retired CEO of GreenPoint Financial Corp. who lost his son in the Sept. 11, 2001, attack, will become the foundation's chairman.

Gov. George Pataki and then-Mayor Rudolph Giuliani created the LMDC shortly after the attack, and Pataki appointed Whitehead to lead it. He has not named a successor.

Whitehead, 84, is a World War II veteran and former investment banker who served as deputy secretary of state in the Reagan administration.

Pataki praised his work as chairman.

"It's an emotionally charged site with a great deal of political and private interests," the governor said. "But he always kept his eye on the public interest, and we can thank him for a job incredibly well done."