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 Pakistani 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.

The hearing was held under tight security. Haqqani's lawyer said the security concerns likely will 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 accused Haqqani in the British daily, The Financial Times, of writing the memo sent in May.

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

The Pakistani commission also ordered Ijaz to appear before the panel at its next hearing January 16. His lawyer said Ijaz has received e-mailed death threats and that the military has been ordered to provide security for him 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.

The U.S. State Department, meanwhile, said it does not want to get involved in the internal politics of Pakistan.

State Department spokeswoman Victoria Nuland confirmed Monday that Secretary of State Hillary Clinton received a letter from Pakistani scholars asking the State Department to intervene in the case on Haqqani's behalf.

The letter urges the U.S. government to “continue to weigh in with key Pakistani leaders and to make appropriate public statements to ensure that Husain Haqqani is not physically harmed and that due process of law is followed.”