U.S. Defense Secretary Leon Panetta on Monday expressed confidence that the U.S. can mend its strained relationship with Pakistan, because the stable relationship with Islamabad is key to win the U.S. war in Afghanistan. Panetta said that restoring the strained relationship with Pakistan is critical to the long-term progress in Afghanistan. \"I think it is going to be important, as we are able to move and progress in our efforts in Afghanistan, that we continue to do outreach in Pakistan,\" he told the U.S. forces press service. \"It is essential to stability in that region that we not only achieve a peaceful resolution with regards to Afghanistan, but that we are able to develop a more stable relationship with Pakistan as well,\" he said. \"If that region is ever going to find peace, it is going to happen not only by achieving stability in Afghanistan, but also by achieving some degree of stability in Pakistan as well.\" The U.S. defense chief conceded that the U.S. relationship with Pakistan has been \"difficult and complicated,\" while emphasizing that \"it is an important relationship, and it is one we have to continue to work at.\" The U.S.-Pakistan relationship was strained after the May 2 U.S. raid inside Pakistan to kill Al-Qaeda mastermind Osama bin Laden, and further worsened after the NATO air attack on a Pakistan military outpost near its border with Afghanistan on Nov. 26 that killed 24 Pakistani soldiers. Pakistan immediately retaliated by blocking the ground supply routes to NATO forces in Afghanistan and ordering the closure of a U.S. military base in Pakistan. \"Obviously what took place has complicated that relationship,\" Panetta said. \"But I think the effort now is to try to see if we can restore that kind of communication with regards to those border incidents.\" He said he was confident that Pakistan will finally agree to reopen the ground supply routes into Afghanistan, adding that, ultimately, restoring a solid relationship goes well beyond supply routes and border operations. \"The most important thing is to keep lines of communication open and make sure we do everything we can to restore some degree of a relationship that will allow us to be able to fulfill our mission,\" he said. Panetta emphasized that the mission of fighting terrorism supports both the U.S.\' and Pakistan\'s interests. \"The terrorism that threatens us also threatens them,\" he said. \"And if we can recognize that, despite our differences, there are some common areas that we share in terms of our security, then I think we can ultimately find a way to resolve our differences and improve our relationship.\"