Latest British fatality in Afghanistan was friend of Prince William

In a statement, royal officials said Prince William, 25, was "deeply saddened" to learn of Roberts' death. He said he remembered the officer with "great respect" and said he was also a "good friend".

Roberts taught William during a posting to Britain's elite military academy, Sandhurst, between 2004 and 2006.

"At this time, his thoughts and prayers are with Lex's wife, Susie, their two young daughters, Alice and Freya, and with all his family and friends," the statement for the prince was quoted as saying by AFP.