WASHINGTON - President Barack Obama paid tributes to US diplomat Richard Holbrooke as confident in himself, curious about others at a memorial Friday in Washington. President Obama described Holbrooke, who died on December 12 after collapsing during a meeting with Secretary of State Hillary Clinton, as a leading light in the generation of diplomats who came of age in Vietnam. He said Holbrookes experience in Vietnam taught him both the limits and possibilities of US power. The memorial was held in the Kennedy Centre. President Asif Ali Zardari, who arrived especially for Holbrookes memorial service, was among the distinguished people present on the occasion. Obama said it was appropriate because President John Kennedys call to service inspired Holbrooke to join the Foreign Service after he graduated from Brown University in 1962. He announced an annual Richard Holbrooke Award for excellence in diplomacy. Other at the memorial included Vice President Joe Biden, Mrs. Clinton and her husband, and President Mikheil Saakashvili of Georgia. Holbrookes last post was Special Envoy to Afghanistan and Pakistan. Former ABC News correspondent Kati Marton, Holbrookes wife, said she learned from him that a life of meaning is more important than a life of ease. His son, Anthony Holbrooke, said he understands now when his father was missing during his childhood thousands of lives were saved. Obama detailed Holbrookes career and his qualities as a diplomat. He also celebrated him as a human being. Like the country he served, Richard contained complexities, Obama said. So full of life, he was a man both confident in himself and curious about others, alive to the world around him. Meanwhile, President Zardari has a telephonic conversation with former US president George W Bush Friday on matters of mutual interest and regional situation, according to Pakistani officials. President Zardari also called Mark Kelly, husband of Congresswoman Gabrielle Giffords, and enquired about the health of the Democratic lawmaker, who was shot in the head in Tuscon, Arizona, on January 8. She is reported to be recovering in intensive care after an emergency surgery performed on her. Zardari said that political discourse needed to be encouraged to eliminate violence from societies. Agencies add: Stating that Holbrooke had secured his place in history, Hillary Clinton said: I am confident that the work he had done and was doing in Afghanistan and Pakistan will also stand the test of time. I personally received the Richard Holbrooke treatment many times. He would give me homework. He would follow me onto a stage as I was about to give a speech, or into my hotel room, or, on at least one occasion, into a ladies room ... in Pakistan, Clinton said amidst laughter and applause from the audience. Hillary praised President Zardaris gesture to travel to Washington for memorial ceremony for Holbrooke and expressed the confidence that the diplomats effort to advance US policy in Pakistan and Afghanistan would stand the test of time.