Admiral Mike Mullen, Chairman of the Joint Chiefs of Staff of United States called on President Asif Ali Zardari at Aiwan-e-Sadr on Saturday. Chief of Army Staff General Ashfaq Parvez Kayani and US Ambassador Anne W. Patterson were also present during the meeting. Matters relating to Pak-US bilateral relations, fight against militancy and regional security situation were discussed during the meeting, according to a report of the Associated Press of Pakistan (APP).