Husain Haqqani maintains he never wrote the unsigned memo, but quit to help defuse the tension, the Los Angeles Times reported.
Pakistani American businessman Mansoor Ijaz said Haqqani asked him to give the memo to then-chairman of the U.S. Joint Chiefs of Staff Mike Mullen. The letter allegedly sought Washington's assistance fending off a possible government overthrow by Pakistan's military after the U.S. raid that killed Osama bin Laden.
Haqqani is a close ally of embattled Pakistani President Asif Ali Zardari, the Times reported.
The memo allegedly says Zardari would eliminate a wing of the Pakistani intelligence agency that maintains relationships with Afghan insurgent groups in exchange for U.S. assistance.