Pakistan's ambassador to the US, Hussain Haqqani, has said he has resigned over claims he wrote a memo to the US asking for its help in reining in the country's powerful military. Haqqani denied on Tuesday any role in writing or delivering the memo. The affair has highlighted the divide between Pakistan's weak civilian government and the military, as well as the role the US plays in the affairs of the country. After the allegations were made last week, Haqqani was summoned to Islamabad to meet the army and intelligence chiefs. Haqqani said on Tuesday evening through his Twitter account that he had sent his resignation to the prime minister, Yousuf Raza Gilani. State television said his resignation had been accepted. A spokesman for the prime minister's office said Haqqani was asked to resign. "I have resigned my services as ambassador and am happy to face an inquiry,'' Haqqani told state news agency.