ISLAMABAD: US Sen. John Kerry arrived in Pakistan late Tuesday on a mission to resolve a diplomatic row over an American official charged by police with murdering two Pakistanis.

The chairman of the US Senate Foreign Relations Committee, who helped spearhead a record $7.5 billion aid package for Pakistan, is well respected in Pakistan.

He will meet government officials to reassure them of long-term US commitment to Pakistan, said a spokeswoman for the US embassy in Islamabad.

A Pakistani official said that Kerry was expected to issue a statement of regret over the incident, though American officials would not confirm that.

The Obama administration asked Kerry to make the trip amid the deterioration in relations between Washington and Islamabad over the Davis case, according to a Congressional official in Washington who spoke on condition of anonymity because he was not authorised to discuss details of the visit publicly.

The official said Kerry did not go to bring Davis back to the US and there was no expectation that he would do so because the Pakistanis have made clear that Davis will not be released in the short term, or at least until the court case against him is resolved.

Kerry ''is there to tone down the rhetoric and reaffirm our partnership,'' the official said.