ISLAMABAD (Reuters) - U.S. Senator John McCain said on Sunday he would like relations between United States and Pakistan to improve as they have a common enemy in the Islamic State and other radical Islamist groups. Relations between Pakistan and United States have been frayed over the past decade, with U.S. officials frustrated by what they term Islamabad’s unwillingness to act against Islamist groups such as the Afghan Taliban and the Haqqani network. Pakistan rejects harboring militants but says there are limits to how much it can do as it is already fighting multiple Islamist groups and is wary of “blowback” in the form of more terror attacks on its soil.  McCain, visiting Pakistan as part of a U.S. delegation, said he had an “excellent meeting” with Pakistani foreign ministry officials. “We come back with a message that we have a common enemy in ISIS, radical Islam and terrorism, and we look forward to closer relations and resolving the differences we have,” McCain told Pakistan’s national PTV channel. Relations between United States and Pakistan were tested again in May by a U.S. drone strike that killed Afghan Taliban chief Mullah Akhtar Mansour on Pakistani soil.  As part of the visit, McCain traveled to Miranshah, the capital of the restive North Waziristan region bordering Afghanistan. The region was effectively run Islamists by groups such as the Pakistani Taliban and the Haqqani network until the Pakistani military launched operations against them in 2014. “I was very impressed with the progress (on the ground),” said McCain, who is the chairman of the Senate Armed Services Committee. “I see us working together in confronting a common challenge – radical Islamic terrorism – and these kinds of meetings are very helpful to both those countries,” McCain added. The Islamic State has struggled to gain a major foothold in Pakistan, analysts say, but officials worry the group may pose a threat in the future.  Pakistan said the country’s top foreign policy official Sartaj Aziz had briefed the U.S. delegation - which includes Senators Lindsey Graham, Benjamin Sasse and Joe Donnelly - about faltering peace talks to end the civil war in Afghanistan. So far China, United States and Pakistan have struggled to persuade the Afghan Taliban to meaningfully embrace the talks. “No country had as much vital stakes in the success of these joint efforts, as Pakistan, (Aziz) remarked,” Pakistan’s foreign ministry said in a statement. 