WASHINGTON (AFP) - General John Allen, the top US commander in Afghanistan, plans to “fully cooperate” with a Pentagon probe into emails he sent to a woman linked to the Petraeus scandal, his lawyer said, while Defence Secretary Leon Panetta ordered US military commanders to carry out a review of ethics training among senior officers amid a widening scandal that cost the CIA chief his job.

“General Allen intends to fully cooperate with the Inspector General investigators and directed his staff to do the same,” Marine Corps Colonel John Baker said in a statement.

He added that Allen, the head of allied forces in Afghanistan whose nomination to become the next Nato supreme commander in Europe has been put on hold, hoped to “resolve those questions as completely and quickly as possible.”

The FBI has uncovered 20,000 to 30,000 pages of correspondence - mostly emails - between Allen and 37-year-old Jill Kelley, a key figure in the scandal that brought down former CIA chief David Petraeus. According to a senior Pentagon official, the married general denies any sexual liaison with the Florida socialite, though the “sheer volume” of correspondence could amount to “conduct unbecoming an officer.” The offense is subject to court-martial under the Uniform Code of Military Justice.

The emails were found during an investigation of allegedly threatening emails sent to Kelley by Paula Broadwell, a married military reservist whose affair with Petraeus was uncovered during the same probe.

Petraeus stepped down over the shock revelation of his extramarital affair with Broadwell, who wrote a fawning biography of the retired four-star general. President Barack Obama has backed Allen, along with Defense Secretary Leon Panetta, currently on a visit to Australia.

Allen’s lawyer said his client would not comment further during the probe, but said he “does sincerely appreciate the support expressed by the president, the secretary of defense, members of Congress and members of the public.”

Panetta, on a tour of Asia, wrote in a memo to the military’s top-ranking officer, General Martin Dempsey that recent cases of misconduct involving the top brass had “the potential to erode public confidence in our leadership and in our system for the enforcement of our high ethical standards”. “Worse, they can be detrimental to the execution of our mission to defend the American people,” he wrote.

Panetta directed Dempsey and the chiefs of the armed services to examine “existing ethics training programmes to determine if they are adequate” and to report back with their findings within a few weeks.

The Pentagon chief then planned to issue an initial report to President Barack Obama on the issue by December 1, according to the memo released to reporters. Panetta also asked Dempsey for his “views on how to better foster a culture of value-based decision-making and stewardship among senior general and flag officers and their staffs”.

Panetta’s trip this week to Australia, Thailand and Cambodia has been often overshadowed by the unfolding Petraeus sex scandal, with the secretary asked about the case at news conferences at each stop.