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 . '' `` Many people would have succumbed , '' Axelrod said of the rupture . Holbrooke , 69 , fell ill Friday morning during a meeting with Secretary of State Hillary Clinton and walked down to the department 's medical unit , a senior State Department official said . He was taken by ambulance to the hospital , the official said . CNN 's Chief Medical Correspondent Sanjay Gupta said the tearing of one of the layers of the walls of the aorta `` happens suddenly . '' It typically is associated with high blood pressure and typically occurs in men between the ages of 50 and 70 . The location of the tear `` would determine what , if any , other side effects would occur , '' Gupta said , adding that `` this is different from a problem people think of with the heart where some of the blood vessels going to the heart become blocked . '' An operation `` typically involves bringing layers of the aorta back together so that no further dissection can occur , '' Gupta said . `` If that 's done quickly and the aorta is intact , meaning it has n't opened up , that can be a very good procedure and can take care of the problem . '' After doctors completed surgery on his aorta Saturday morning , Holbrooke was joined by his family , State Department spokesman P.J . Crowley said . Secretary Clinton visited Holbrooke at the hospital on Saturday , the State Department said . Holbrooke is a career diplomat best known for brokering the peace agreement between Bosnian factions in 1995 that became the Dayton accords . President Barack Obama called the diplomat 's wife , Kati , and told her he and first lady Michelle Obama have Holbrooke in their prayers , the White House said in a statement . `` 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 , '' the president said . CNN 's Elise Labott contributed to this report .
NEW : A top U.S. diplomat is in critical condition at a D.C. hospital , the state department says . NEW : Richard Holbrooke 's wife talks Sunday with Afghanistan and Pakistan 's presidents . Holbrooke , 69 , fell ill Friday and underwent surgery for a tear in his aorta . A senior White House adviser says Holbrooke 's toughness is helping him .