Tom Casey, the US deputy state department spokesman, said on Wednesday: "I would expect that he will provide the same message in private to Pakistani officials that we have been saying in public.
"We want to see all moderate political forces be able to work together. We continue to want to see elections move forward in a free, fair and transparent manner [and] we want to see the emergency decree lifted."
Opposition alliance
In a separate development, the leaders of Pakistan's two main opposition parties are reported to be working to form an alliance.
The proposed pact was revealed by Benazir Bhutto, a former prime minister and head of the Pakistan Peoples' Party, who remains under house arrest in her Lahore residence.
Bhutto has called on Musharraf to step down as president and said she is seeking a partnership with Nawaz Sharif, her long-time rival and the exiled leader of the Pakistan Muslim League.
She said: "[Musharraf] must quit as president and as chief of army staff.
"I call on the international community to stop backing ... the man whose dictatorship threatens to engulf this nuclear-armed state in chaos," she said.
She also said for the first time that she would not serve under Musharraf should he win the elections he has promised by January 9.
"I would not serve as prime minister under a man who has repeatedly broken his promises, who is a dictator," said Bhutto, who has previously held talks with Musharraf on sharing power.
On Wednesday, Sharif said he was ready to work with Bhutto, against Musharraf.
"We are ready to set aside our differences with the People's Party and work for the return of democratic rule," Sharif said by telephone from Saudi Arabia, referring to Bhutto's party.
Asked whether there was any possibility of a broad opposition coalition against Musharraf, Sharif said: "It's the need of the hour.
"There is no room for dictatorship in Pakistan. We don't accept this set-up," he said.
Defiant Musharraf
Musharraf meanwhile spent the day in a series of interviews aimed at defending his decision to impose emergency rule. He said emergency rule would stay in place until after the elections.
"Emergency is not meant to rig elections," he said. "Emergency is in fact meant to make sure that the elections are held in a peaceful manner.
"The issue of transparency; We are inviting any amount of observers to Pakistan to see [the election]. Let them come and see the transparency of the election," he said.
"What the the oppositon is talking about is agitation. They want to disturb law and order and undermine governance."