US president Barack Obama said he was praying for critically-ill diplomat Richard Holbrooke, calling him “a towering figure in American foreign policy”.
Mr Holbrooke, 69, the president’s special envoy for Afghanistan and Pakistan, is in a critical condition after undergoing surgery on a torn aorta.
The veteran diplomat was meeting secretary of state Hillary Clinton at the US State Department on Friday when he suddenly collapsed and was rushed to nearby George Washington University Hospital.
Mrs Clinton joined his family and other senior administration officials at the hospital.
“Richard Holbrooke is a towering figure in American foreign policy, a critical member of my Afghanistan and Pakistan team, and a tireless public servant who has won the admiration of the American people and people around the world,” Mr Obama said.
He said he had told Mr Holbrooke’s wife Kati that “Michelle and I are praying for Richard”.
“We continue to pray for his recovery, and support his family in this difficult time,” said the president.
Earlier, State Department spokesman PJ Crowley said the surgery on Mr Holbrooke’s torn aorta – a main artery connected to the heart – was completed on Saturday morning.
Early in his administration Mr Obama named Mr Holbrooke special envoy for Afghanistan and Pakistan.
The diplomat is perhaps best known for helping broker the 1995 agreement that ended the war in Bosnia. He served as US ambassador to the United Nations during the Clinton administration and was US ambassador to Germany from 1993 to 1994, then assistant secretary of state for European affairs.