Lebanon's Prime Minister Najib Mikati wrote on his Twitter account: "Sincere condolences to journalist Anthony Shadid's (RIP) family, friends & New York Times colleagues. I've known and admired him personally. N.M."
Shadid's father, Buddy Shadid, told The Associated Press on Thursday his son had asthma all his life and had medication with him.
"(But) he was walking to the border because it was too dangerous to ride in the car," the father said. "He was walking behind some horses — he's more allergic to those than anything else — and he had an asthma attack."
Shadid, an American of Lebanese descent, had a wife, Nada Bakri, and a son and a daughter. He had worked previously for the AP, The Washington Post and The Boston Globe. He won Pulitzer Prizes for international reporting in 2004 and 2010 when he was with the Post.
In 2004, the Pulitzer Board praised "his extraordinary ability to capture, at personal peril, the voices and emotions of Iraqis as their country was invaded, their leader toppled and their way of life upended."
Shadid also was the author of three books, including "House of Stone: A Memoir of Home, Family, and a Lost Middle East," in which he wrote about restoring his family's home in Lebanon, forthcoming next month from Houghton Mifflin Harcourt.