US Defence Secretary Robert Gates has warned that President Pervez Musharraf's effectiveness as a US ally depends on what happens next in the unfolding political crisis in Pakistan.
Admiral Michael Mullen, the chairman of the Joint Chiefs of staff, meanwhile said he was confident that Pakistan's nuclear weapons remain secure despite 12 days of turmoil since Musharraf imposed a state of emergency.
Gates said Musharraf has been an important ally to the United States, but he needed to end the state of emergency as soon as possible and step down as army chief of staff.
Musharraf's "ability to continue to be a partner in the war on terror very much depends on how events unfold over the next few weeks in Pakistan," he told a Pentagon news conference yesterday.
Mullen, who joined Gates at the news conference, said US military relations with Pakistan continued unchanged.
In the most emphatic US statement yet on the security of the Pakistani nuclear arsenal, Mullen said there was no indication that its stockpile of nuclear weapons was in jeopardy.
"We obviously have been conscious about what Pakistan has done in the nuclear realm for many years. And ... Into the current crisis we've paid an awful lot of attention, actually as we have in the past."
"So I am confident at this point that they are secure, and I have seen absolutely no indication of the contrary," he said.
"We're very watchful, mindful certainly of the general concerns and what the potential could be. But we don't see any of that potential being fulfilled at the current time," he said.