According to administration officials quoted in the American media, Secretary of State Hillary Clinton is expected to announce the appointment during a major policy speech on Afghanistan and Pakistan at the Asia Society in New York on Friday.

Grossman is currently vice chairman of the Cohen Group, a Washington-based consulting group headed by former US defence secretary and senator William Cohen.

The post for special envoy has been vacant since December, when the 68-year-old Holbrooke, a famous diplomat, died.

Between 2001 and 2005, Grossman served as US Under-secretary of state for political affairs, according to his biography on the Cohen Group's website. He was assistant secretary of state for European affairs in the three years before that, and between 1994 and 1997 he was the US ambassador to Turkey.

The CNN reported that last July, Grossman penned a report for The

German Marshall Fund for the United States in which he spoke positively of a plan to turn Afghanistan's extensive opium poppy fields directly into green biofuel, saying counter-narcotics goals and environmental  concerns could be matched by such a project.

While serving under President George W. Bush, Grossman gained headlines in 2002 when he criticised the then-proposed International Criminal Court as "an institution of unchecked power."