A cellphone used by Osama bin Laden\'s courier appears to show that the Al-Qaeda leader was aided by militants linked to Pakistani intelligence, The New York Times said. Citing US officials briefed on an investigation into the phone, the Times said calls from the device were traced to Harakat-ul-Mujahideen, a militant group linked to Pakistan\'s powerful Inter-Services Intelligence (ISI) agency. \"It\'s a serious lead,\" one US official told the Times. \"It\'s an avenue we\'re investigating.\" Another US official told the daily that the link was not, however, a \"smoking gun\" that definitively linked bin Laden to the ISI, as it was unclear if the calls were related to him. The phone was seized during a daring US commando raid in Pakistan last month in which both bin Laden and his courier were killed. The Pakistan-based Harakat ul-Mujahideen is classified as a \"terrorist\" organisation by the United States. Defence analysis group Jane\'s said the outfit has conducted raids on Indian security positions and is active in Pakistan-administered Kashmir. The Times said it has maintained clandestine links with the ISI for years. Relations between Pakistan and the United States, tense at the best of times, deteriorated sharply over the bin Laden raid, which humiliated the Pakistani military and invited allegations of incompetence and complicity. As US President Barack Obama seeks to bring an end to the war in Pakistan\'s neighbor Afghanistan, US and Pakistani officials have sought to play down any unease between them.