The US acknowledged that its ally Pakistan keeps ties with anti-India terror group Lashkar-e-Taiba. In response to a question at National Defense University Defense Secretary Leon Panetta said such issues make ties with Islamabad “complicated. Panetta also cited other difficulties that have crept up in US-Pak ties including the visa problem. However, Panetta and Secretary of State Hillary Clinton argued in a joint public appearance that it was not possible to cut off relationship with Pakistan as the nuclear-armed country provided some crucial cooperation in fighting al Qaeda in Afghanistan. During a public forum with Secretary of State Hillary Clinton in Washington on Tuesday, Panetta said Pakistan has ties to the Haqqani network in the country's northwest that conducts cross-border attacks on U.S. forces in Afghanistan as well as with Lashkar-e-Taiba militants who attacked India. Both groups are listed by the United States as terrorist organizations.