Bangkok -

Defence Secretary Leon Panetta said on Thursday he knows of no other senior US military officers being linked to the David Petraeus investigation that has ensnared the top US commander in Afghanistan, General John Allen.

Speaking at a Bangkok news conference, Panetta said he retains confidence in Allen.

Panetta said he is not going to characterise in any way the nature of the emails and other correspondence between Allen and Florida socialite Jill Kelley, which others have called flirtatious and potentially problematic for the Marine general.

Panetta said he wants to be careful with his words in order not to jeopardise the Pentagon inspector general investigation he ordered on Monday.

Panetta also told reporters that he could not rule out the possibility that the Taliban in Afghanistan would try to use Petraeus' admission of an extramarital affair with his biographer, Paula Broadwell, for propaganda purposes. Petraeus, who resigned Friday from his post as CIA director, was Allen's predecessor as top commander in Afghanistan. - Sapa-AP