Washington (CNN) -- U.S. diplomat Richard Holbrooke was in critical condition at a Washington hospital Sunday night, after undergoing surgery on Saturday to repair a tear in his aorta, the State Department said. Holbrooke underwent another procedure on Sunday to improve his circulation, the department said in a statement Sunday night. Relatives, friends, colleagues and staff are by his side, and his wife Kati Marton spoke Sunday with Afghan President Hamid Kharzai and Pakistani President Asif Ali Zardari. The State Department did not provide details of Marton's conversation with the presidents. Appearing earlier in the day on the CNN program "State of the Union," senior White House adviser David Axelrod said that Holbrooke was "fighting" the heart problem at George Washington University Hospital. He called President Barack Obama's special representative to Pakistan and Afghanistan "a very tough person."
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NEW: A top U.S. diplomat is in critical condition at a D.C. hospital, the state department says
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NEW: Richard Holbrooke's wife talks Sunday with Afghanistan and Pakistan's presidents
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Holbrooke, 69, fell ill Friday and underwent surgery for a tear in his aorta
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A senior White House adviser says Holbrooke's toughness is helping him
"Many people would have succumbed," @placeholder said of the rupture.