Thomas P. Mack, 60, a retired foreign service officer for the State Department's Agency for International Development (AID), died at sea Thursday after a heart attack. He was serving as a relief officer aboard the "Oceanic," a research vessel out of Woods Hole, Mass., when he was stricken.

A graduate of the U.S. Merchant Marine Academy, Mr. Mack was a Merchant Marine commander in the Atlantic and Pacific theaters in World War II.

He joined the State Department in 1952 and worked for the old International Cooperation Administration before AID was established in 1961. His AID assignments included tours in Pakistan, Vietnam, Thailand, Bangladesh, Hong Kong and Guyana.

After retiring in 1978, Mr. Mack began working as a relief officer on various commercial and research vessels.

He was born in Revere, Mass., and graduated from Georgetown University's School of Foreign Service and Johns Hopkins University's School of Advanced International Studies. He earned a law degree from LaSalle University and a doctorate in geography from the University of Dacca in Bangladesh. He lived in Alexandria.

Survivors include his wife, Mary B., a son, Brian X., and a daughter, Kim A., all of Alexandria; two other sons, Air Force Capt. Thomas P. Jr., of Denver, and Army 1st Lt. Christopher, of San Francisco; another daughter, Maureen M. Peterson of Toronto; three brothers, Joseph, John and William of Boston, and a granddaughter.