PERTH: United States Defence Secretary Leon Panetta on Wednesday backed the top US commander in Afghanistan, saying he had his “continued confidence”.

General John Allen was placed under investigation after FBI agents probing email threats sent by former CIA director David Petraeus' mistress stumbled upon messages he had sent to another woman at the centre of the scandal.

“General Allen is doing an excellent job at Isaf,” Panetta told reporters in Perth.

“He certainly has my continued confidence to lead our forces and continue the fight.”