ISLAMABAD  -Chairman of the US Joint Chiefs of Staff Admiral Michael Mullen on Saturday made a surprise visit to Pakistan and met with Chief of Army Staff Gen Ashfaq Parvez Kayani at the General Headquarters in Rawalpindi. He also met with Chairman Joint Chiefs of Staff Committee Gen Tariq Majeed. Admiral Mullen discussed the current situation in the region with Army Chief Gen Ashfaq Parvez Kayani amid recent flare up in the areas bordering Pakistan and Afghanistan. Kayani reportedly raised the issue of attacks on Pakistani forces in Momand tribal region by US-led forces in Afghanistan that killed 11 paramilitary personnel last month. He also referred to Friday's attack on a Pakistani border post and expressed concern that such incidents might affect cooperation in the war on terror. "They discussed the war on terror and military cooperation between Pakistan and the US," TV channels reported. Kayani briefed Mullen on his force's efforts to counter militancy in the tribal areas and NWFP. The two officials also discussed the situation along the Pakistan-Afghanistan border.