LONDON, July 3 (Xinhua) -- The British Ministry of Defence said that an army officer killed in an explosion was the most senior one to have died in Afghanistan since operations began in 2001.

    Lieutenant Colonel Rupert Thorneloe, commanding officer of the 1st Battalion Welsh Guards, was killed in Helmand province, southern Afghanistan on Wednesday when an explosive device was detonated under the vehicle he was traveling in, the ministry said on Thursday night.

    Prince Charles, reported to have known Lt. Col. Thorneloe well, was "deeply saddened", a Clarence House spokesman said.

    A total of 171 British soldiers have died in Afghanistan since 2001.