Pakistani President Asif Ali Zardari on Tuesday paid glowing tribute to Richard Holbrooke, calling the late US special envoy to the region a "friend of Pakistan".
Holbrooke died in Washington on Monday aged 69, three days after falling ill at work and following surgery for a torn aorta.
"Pakistan has lost a friend. He was an accomplished and experienced diplomat, who quickly gained the confidence of his interlocutors," Zardari was quoted as saying in an official statement.
He called Holbrooke a "key player in international diplomacy to bring peace to Bosnia and in confronting militancy in our part of the world".
Zardari described the late US envoy as a personal friend of both himself and his late wife, assassinated former prime minister Benazir Bhutto.
"The best tribute to him is to reiterate our resolve to root out extremism and usher in peace," Zardari said.
Holbrooke, the US special envoy for Afghanistan and Pakistan, was one of America's most experienced diplomats with an illustrious career spanning nearly 50 years.
He had the daunting task of pushing Kabul and Islamabad to work together against resurgent Al-Qaeda and Taliban insurgencies in Afghanistan and Pakistan.
Holbrooke maintained a lower profile in his latest assignment than when he brokered the 1995 agreement that ended three years of war in Bosnia.
Although Islamabad is a key US ally in the war in neighbouring Afghanistan, the alliance is deeply unpopular within Pakistan, where anti-Americanism has been fanned by US drone attacks on militants in the country's tribal belt.