"I have requested PM Gilani to accept my resignation as Pakistan Ambasssador to US," Husain Haqqani just wrote on his Twitter page.
And he followed that with this statement: "I have much to contribute to building a new Pakistan free of bigotry & intolerance. Will focus energies on that."
Pakistan's DAWN news group says Prime Minister Yousuf Raza Gilani "has reportedly accepted Haqqani's resignation."
Word that Haqqani has submitted his resignation follows the ambassador's return to Pakistan "to answer questions about his alleged role in a secret memo scandal."
"The controversy centers on a memo that was sent in May to Adm. Mike Mullen, the top U.S. military official at the time, asking for his help in reining in Pakistan's powerful military after the covert American raid that killed Osama bin Laden in a Pakistani garrison town.
"Mansoor Ijaz, a U.S. citizen of Pakistani origin, has claimed that ... Haqqani orchestrated the memo, which has been published in the media and does not include an author's name. ... Haqqani has denied the allegations."
Called "memogate" in Pakistan, the controversy has caused scandal there because of the implication that someone in authority was appealing to the U.S. for such help.
Haqqani has been a guest several times on NPR broadcasts. In July, he told All Things Considered host Robert Siegel that:
"Pakistan and the United States have a complex, multidimensional relationship. Both countries need each other. Occasionally there are differences between the best of allies. We've seen that through history: France and the United States had problems, Britain and the United States did not always agree on the conduct of the Second World War.
"So I think what we see is basically a difficult, complex relationship playing out in an age of media glare. But what comes in the media glare is not always what happens in private between us as allies."