Chicago: A US judge has imposed a 35-year prison sentence for an American who played a key role in the 2008 terrorist attack on Mumbai, India, that killed more than 160 people.

David Coleman Headley conducted meticulous scouting missions before 10 gunmen carried out the devastating assault often called India's 9/11.

The 52-year-old was sentenced Thursday on 12 counts. Those included conspiracy to aid the Pakistani group Lashkar-e-Taiba, which mounted the attacks on the landmark Taj Mahal Hotel and other targets.

The maximum sentence was life in prison. Headley pleaded guilty and cooperated to avoid the death penalty and extradition to India.

Headley was born Daood Gilani to a Pakistani father and American mother. He changed his name in 2006 to travel more easily to and from India.