A U.S. Senate delegation led by John McCain, the chairman of the Armed Services Committee, has visited a Pakistani tribal region that has long been considered a stronghold of militant groups such as Al-Qaeda and the Taliban.
The four-member delegation visited North Waziristan, near the Afghan border, on July 3, Pakistan’s Foreign Office said in a statement.
It said the senators had held talks with Sartaj Aziz, the prime minister's top foreign-affairs adviser, to discuss Pakistani-U.S. ties, as well as the situation in Afghanistan.
McCain posted pictures from the trip on his Twitter account and also tweeted that the delegation had a "good meeting" with Pakistan Army chief Raheel Sharif, "discussing regional security challenges."
Foreigners and journalists are largely banned from the tribal region, where the Pakistani Army launched an operation in 2014 to root out militancy there.
The United States carries out drone attacks in the area, targeting Taliban and Al-Qaeda leaders.
The relationship between the United States and Pakistan has been strained in recent years.
Some U.S. officials accuse Pakistan of not doing enough to use its influence to persuade the Afghan Taliban to renounce violence.
Pakistan has been critical of the U.S. drone campaign, which has killed scores of civilians over the years.