The agreement was made after Mr Kerry met senior Pakistani politicians, including new PM Nawaz Sharif.

The talks were stalled after 24 Pakistani soldiers were killed in US air strikes on a Pakistani post on the Afghan border in 2011.

Relations were also strained by the US killing of al-Qaeda leader Osama Bin Laden in May of that year.

Speaking after the talks on Thursday, Mr Kerry said they were "constructive" and "positive".

"We are here to speak honestly with each other, openly about any gaps that may exist that we want to try to bridge," Mr Kerry said. "Our people deserve that we talk directly."

He said the two sides were serious about overcoming past irritants and that he had invited the new prime minister to Washington to meet US President Barack Obama.

It is Mr Kerry's first trip to Pakistan as secretary of state, although he has a long history of dealing with Pakistan as former chairman of the Senate Foreign Relations Committee.

Before the pair began their talks, Mr Sharif described him as "a wonderful friend", while Mr Kerry replied that he "had the pleasure of visiting Mr Sharif's home and having a number of meals with him''.

The secretary of state paid tribute to Mr Sharif's victory at the polls. It marked the first time that an elected civilian Pakistani government completed a full term in office and handed over to another.

"This is a historic transition that just took place. Nobody should diminish it," he told US embassy staff.

US officials travelling with Mr Kerry said Pakistan - although still formulating its counter-terrorism strategy following a spate of militant attacks - is likely to continue clampdowns on militants, but also engage them in talks.

The last visit by a US secretary of state was in 2011, after Osama Bin Laden was killed.