Pakistan's former ambassador to the United States has denied any connection to a memo sent to Washington asking for U.S. help in preventing a purported army coup.

In his first appearance before a Supreme Court commission Monday, Husain Haqqani said he had “no role in creating, drafting and/or delivering” the memo to Admiral Mike Mullen, the top U.S. military official at the time.

Haqqani appeared before the commission under tight security. His lawyer said the security concerns will likely prevent the former diplomat from appearing before the panel again.

The existence of the document came to light in October when Pakistani-American businessman Mansoor Ijaz wrote a column in The Financial Times accusing Haqqani of writing the memo requesting U.S. assistance to prevent a coup. The request was reportedly sent to Mullen in May.

U.S. military officials have said Admiral Mullen received the memo but did not find it credible.

The Pakistani commission on Monday also ordered Ijaz to appear before the panel at its next hearing on January 16.

Ijaz's lawyer told reporters that his client has received e-mailed death threats and that the military has been ordered to provide security for the Pakistani-American businessman when he arrives in Pakistan.

Haqqani returned to Pakistan in November and resigned as ambassador.

The Supreme Court appointed the three-judge commission last month to investigate the circumstances surrounding the unsigned memo.