"While it may be that Mr. Holbrooke can never truly be replaced, the need for a new mediator to deal with the tensions in Afghanistan and Pakistan is most pressing," said Ashraf Qazi, chairman of the Council on Pakistan Relations.
"Holbrooke possessed not only a special sensitivity but a deep, personal concern for the people of South Asia. Literally his last words on earth were to implore the world to bring an end to conflict in part of the world, as he had in Bosnia before," Qazi said.
The group, representing Pakistani Americans, was often in contact with Holbrooke aides.
"Holbrooke's rough outside demeanor hid a genuine compassion for South Asia," Qazi added.
"The ever-growing threat of terrorism and the powder keg that exists in Kashmir cannot go unattended much longer," he said. "There has to be a single person who can work daily with people in the area to bring a lasting peace."