Drone strikes by the United States was the main focus of a meeting of U.S. Defense chief Chuck Hagel and Pakistani officials Monday, authorities said. Prime Minister Nawaz Sharif raised the subject of U.S. drone strikes in Pakistan's tribal belt, a highly contentious issue that his electoral rivals have used against him, the New York Times reported. Supporters of challenger Imran Kahn a former cricket player, have partially blocked NATO supply lines through Khyber-Pakhtunkwa, the northwestern province that is controlled by Khan's Pakistan Tehreek-e-Insaf party. Sharif said drone strikes were counterproductive to the Pakistan government's work to combat terrorism and extremism on an ongoing basis, the Associated Press of Pakistan reported. Sharif and Hagel also discussed regional matters of mutual interest, Pakistan's Foreign Office said. "The two leaders agreed to work together to strengthen Pakistan-U.S. relations and advance the shared interest of a stable, secure and prosperous Pakistan and the region," a statement issued by Foreign Office said. Hagel also met with Pakistan's new military leader, Lt. Gen. Raheel Sharif, at Rawalpindi, the garrison city near Islamabad. In a statement Sharif, no relation to the prime minister, said the defense relationship between the two countries, bilateral ties and regional stability were discussed. Before the meetings, a senior Pentagon official said while the United States and Pakistan have a "significant overlap" of regional security interests, "it has not been 100 percent." Washington has claimed Pakistani intelligence officials were trying to stake influence in Afghanistan through covert support for terrorist groups that target Americans and Afghans, the Times said. The Pakistani government has expressed outrage over U.S. drone strikes against militant targets in Pakistan, some of which have killed civilians. "There is some friction in the relationship," the Pentagon official told the Times. "One of the reasons the secretary is going to Pakistan is to address those issues head-on."