A senior US envoy has urged Pakistani President Pervez Musharraf to lift emergency rule and free opponents ahead of elections due in January.
"Emergency rule is not compatible with free, fair and credible elections," said John Negroponte, a day after meeting the Pakistani leader.
Gen Musharraf imposed emergency rule two weeks ago following growing opposition and unrest.
He has insisted it can only be lifted once the security situation improves.
Mr Negroponte, the US deputy secretary of state, said he had urged Gen Musharraf to stick to his pledge to step down as head of the army, and encouraged him to release political prisoners.
"Recent political actions against protesters, suppression of the media and the arrests of political and human rights leaders, runs directly counter to reforms that have been undertaken in recent years," he said.
However, the US envoy praised Gen Musharraf as a valued ally in the war on terror and welcomed the Pakistani leader's promise to hold elections on 9 January.
'Fight against extremism'
On Saturday an aide to Gen Musharraf said he had told Mr Negroponte that the constitution could only be restored when law and order had been re-imposed.
"He told the envoy that the emergency is meant to reinforce and strengthen the law enforcement apparatus in the fight against militancy and extremism," the aide told AFP news agency.
The BBC's Barbara Plett in Islamabad says Mr Negroponte made it clear that the US did not accept Mr Musharraf's arguments for emergency rule.
He did not signal what kind of pressure might be brought to bear on the Pakistani leader, although American officials said he had raised the issue of cuts in aid to Pakistan.
Mr Negroponte is the most senior US official to have met Gen Musharraf since the imposition of emergency rule on 3 November.
He also met other high-ranking Pakistani officials and spoke to opposition leader Benazir Bhutto by phone.
Mr Negroponte said he had encouraged Gen Musharraf to resume power-sharing talks with Ms Bhutto.
Those talks broke down as Ms Bhutto threatened to lead mass protests against emergency rule, and was then placed under house arrest. She has now been released, but has appeared to rule out re-starting negotiations.
"If steps were taken by both sides to move back towards the kind of reconciliation discussions they had been having previously, we think that could be very positive," Mr Negroponte said.
Talks could help "pull the political actors back from the atmosphere of brinksmanship and confrontation", he said.