In meetings with President Asif Ali Zardari and Prime Minister Syed Yousuf Raza Gilani, Clinton stressed the importance of Pakistan's support in defeating the Taliban in the 9-year-old Afghanistan war, The New York Times reported.
The United States, which calls on the Pakistani military to fight harder against Taliban militants in tribal regions on the Afghanistan-Pakistan border, faces widespread anti-American sentiment among Pakistanis.
But relations between the two governments have improved since Clinton's last visit in October when she faced hostile audiences and suggested Pakistani officials knew the whereabouts of Osama bin Laden and a deputy.
"We needed to change the core of the relationship with Pakistan," Richard Holbrooke, the special representative to Afghanistan and Pakistan, said. "The evolution of the strategic dialogue, and the fact that we are delivering, is producing a change in Pakistani attitudes."
Dawn reported opinion polls indicate widespread doubts among Pakistanis about long-term U.S. intentions. Many cite being abandoned after the Soviet withdrawal from Afghanistan, the Pakistan-based news network reported.
U.S. officials have also urged Pakistan to do more to battle home-grown militants, among them, the suspect who pleaded guilty in the failed Times Square car bombing.
"When this administration came in there was a huge trust gap between Pakistan and the U.S.," Holbrooke adviser Vali Nasr told Dawn. "Pakistanis are beginning to develop much more knowledge about what our intentions are and with that comes trust."
During the visit, Clinton is to pledge $500 million in American aid to Pakistan to go toward public health, water distribution, agriculture and a 60-bed hospital in Karachi.
Obama administration officials told the Times they did not know if Clinton would bring up Pakistan's plans to buy two nuclear reactors from China.
After more talks in Pakistan Monday, Clinton is to head to Afghanistan for an international conference Tuesday bringing together diplomats from dozens of countries along with the United Nations and NATO leaders. The secretary is expected to urge Afghanistan and Pakistan to work together to root out Taliban militants.