Kerry arrived in Islamabad on Sunday, after Pakistan's parliament said there must be no repeat of the commando operation that killed bin Laden and insisting US drone strikes targeting extremists on its territory must end.
The first senior US visitor since the al-Qaeda kingpin's death, Kerry was to meet President Asif Ali Zardari and Prime Minister Yousuf Raza Gilani, foreign office spokesperson Tehmina Janjua said.
Kerry told reporters in the Afghan capital Kabul on Sunday, before travelling to Pakistan, that US relations with its nuclear-armed ally were at a "critical moment".
"We need to find a way to march forward if it is possible. If it is not possible, there are a set of downside consequences that can be profound," said Kerry, whose trip to the region has been endorsed by President Barack Obama.
He said he was he was ready to listen to Pakistan's leaders but the discovery of the al-Qaeda chief living close to Islamabad meant talks had to "resolve some very serious issues".
Co-operation under review
The raid has rocked Pakistan's security establishment, with its government, intelligence services and military widely accused of incompetence or complicity over the presence of bin Laden in a garrison town near the capital.
Pakistan has meanwhile vowed to review intelligence co-operation with the United States following the raid, which its foreign ministry called an "unauthorised unilateral action".
While leaders of the US Congress have voiced support for preserving aid to Pakistan, other lawmakers say Pakistan can no longer be trusted and funding should be trimmed.
The United States has given about $18bn to Pakistan since the September 11 2001 attacks, when the nuclear-armed nation officially ended support for Afghanistan's Taliban and agreed to work with the United States.
While most of the money has gone to the military, Congress in 2009 authorised $7.5bn over five years to help bolster the weak civilian government by building schools, roads and democratic institutions.
Kerry, chairperson of the influential Senate Foreign Relations committee, also repeated Washington's belief that Pakistani authorities know where Taliban safe havens harbouring the leaders of Afghanistan's insurgency are located.
Amicable resolution
"There is some evidence of Pakistan government knowledge of some of these activities in ways that is very disturbing," he told reporters in Kabul, adding that he would raise the long-standing issue in Islamabad.
But Kerry also sought to dampen the diplomatic fallout from the bin Laden raid, which severely strained ties with the US and stirred renewed anti-American sentiment in Pakistan.
"It's important to try also to not allow the passions of a moment to cloud over the larger goal that is in both of our interests," he said in reference to efforts to combat Islamist militancy.
US Secretary of State Hillary Clinton telephoned President Asif Zardari on Sunday during which "both agreed to resolve the issues amicably and move forward", according to an official statement.
Many Pakistanis have been outraged at the perceived impunity of the US raid, while asking whether their military was too incompetent to know bin Laden was living close to a major forces academy, or, worse, conspired to protect him.
Pakistan's parliament on Saturday called on the government to appoint an independent commission to ensure the US operation on its territory was not repeated and condemned CIA-operated drone strikes.
US missile strikes doubled last year, with more than 100 operations killing over 670 people, according to an AFP tally, while the CIA has said the covert programme has severely disrupted al-Qaeda's leadership.
- AFP