Husain Haqqani, Pakistan's ambassador to the US, on Saturday left for Islamabad after an explanation was sought from him over a secret memo to Washington claiming that President Asif Ali Zardari had feared a military coup. Haqqani wrote on Twitter: "On way to motherland, Pakistan". Pakistani businessman Mansoor Ijaz alleged in a column in the Financial Times last month that a senior Pakistani diplomat asked for help in getting a message from Zardari to then chairman of the US Joint Chiefs of Staff Mike Mullen. Ijaz alleged that Zardari feared a military takeover following the US raid that killed Osama bin Laden in Pakistan in May and brought unprecedented public scrutiny on Pakistani leaders. Earlier Prime Minister Yousuf Raza Gilani said he sought an explanation from Haqqani over the secret memo.