Iran's chief diplomat also met with Pakistan's Army Chief of Staff Lieutenant General Qamar Javed Bajwa.
Speaking at a news briefing at the Pentagon on Wednesday, Mattis said Pompeo and General Dunford will meet with PM Imran and other Pakistani leaders and discuss relations between the two countries.
He said Iranian Foreign Minister Javad Zarif is arriving in Islamabad on Thursday for talks with the Pakistani leadership, which is a positive development.
"Islamabad does not have that political clout, and Pakistan's own relations with the U.S. are hanging with a fragile thread that could break any moment", said geopolitical analyst, Qamar Cheema.
Prime Minister said that human resource development is a priority of his Government.
Bajwa thanked Khan for his visit and his confidence in the country's armed forces and assured him that the army shall, "God willing, continue to deliver on nation's expectations of defending the motherland at all costs and sacrifices". Then she was asked how the Pakistanis could have got it so wrong if the United States says it did indeed discus terror.
Commenting upon the prime minister's visit to the GHQ, Information and Broadcasting Minister Fawad Chaudhry said it was wonderful. A detailed briefing in GHQ was of great value.
Fawad Chaudhry asserted the government would counter all the challenges confronting Pakistan with close coordination and cooperation amongst all the institutions.
The two sides also discussed ways to develop military and security cooperation and expressed hope that Tehran and Islamabad would further increase relations given their common goals, interests and border concerns.
Bajwa had congratulated Khan on assuming the top ministerial job during their meeting. They expressed resolve to bring enduring peace and stability in the country while continuing efforts for regional peace, the Prime Minister Office had said in a statement.
He said Khan wants to focus on his new government, sworn in earlier this month, and a looming currency crisis which threatens to derail the fast-growing economy.