NEW CHAPTER

Both sides appear keen to start a new chapter in their relationship. President Barack Obama hailed Sharif's victory in May as a "significant milestone" for Pakistan's democracy.

Speaking on condition of anonymity, the official praised Sharif for taking "pretty remarkable" steps to address domestic economic problems such as crippling power shortages.

"Unlike previous visits, we are not going at a moment of crisis, which has defined the relationship over the last several years, but at a moment of quite unique and aligned interests," said the US official.

"It is an alignment of several factors that made this the right time to go to begin a series of substantive, meaty and important discussions with the new civilian government and a range of other stakeholders in Pakistan," the official added.

Security will be the toughest item on the agenda. The Haqqani network is allied to the Afghan Taliban and has bases in the rugged borderland between Afghanistan and Pakistan where other militant al Qaeda-linked groups are also based.

Another US administration official said the Haqqani network remained "resilient" despite US sanctions and efforts to choke off its funding.

While the issue of extremist groups operating in Pakistan was a priority for the talks, the official emphasised that the intention was not to tell the Pakistanis what to do.

"They are working on their own counter-terrorism strategy. We just need to wait and see what they come up with internally and how we can coordinate both in our bilateral relationship and with joint cooperation," the official said.

"Fostering or helping in any way to provide some sort of base for extremism is ultimately not in any our interests including Pakistan's interests.

"We will have to see where the new government is on this and what they are willing to do, and how they see it as part of their broader efforts at promoting stability."

State Department spokeswoman Jen Psaki said Kerry would also visit Britain on his way back to the United States at the end of the week.