Leader of the opposition in National Assembly Ch Nisar Ali Khan Friday urged the United States to clarify its policy regarding Pakistan. During his meeting with U.S. Ambassador, Anne W Patterson here at Punjab House, Ch Nisar expressed serious concerns over US attacks in Pakistani territory and said the US should respect Pakistan's sovereignty. The PML-N leader also criticized U.S. Assistant Secretary of State Richard Boucher's recent statement about the ISI, saying the US should not interfere in Pakistan's internal affairs.