The Obama administration has “no reason to speculate” about the physical or political future of Pakistani President Asif Ali Zardari, Secretary of State Hillary Rodham Clinton said Thursday, adding that U.S. officials “expect that he will receive the treatment that he is seeking and then be able to return in full health to his duties.”

Zardari left Pakistan on Tuesday for Dubai, where aides said he has been receiving medical care for a heart ailment. His departure had sparked rumors that he intends to resign.

The speculation is grounded in strong domestic criticism of the government’s ties with the United States following the killing of 24 Pakistani soldiers in a U.S. airstrike near the Afghanistan border almost two weeks ago.

Since the incident, Pakistan has closed supply routes that allow U.S. and coalition military convoys to cross into Afghanistan. On Thursday, more than 20 Afghanistan-bound fuel tankers were torched near the southwestern Pakistani city of Quetta, the Associated Press reported.

In an interview this week, Prime Minister Yousuf Raza Gilani said that new agreements were being negotiated with the Obama administration to ensure that the two countries “respected each other’s red lines” regarding sovereignty and rules of engagement along the border.

Pakistani demands include a smaller CIA footprint in the country and more information on what U.S. intelligence agents are doing there; more control over and information about drone strikes; and a greater role for Pakistan in Afghan reconciliation efforts.

In a statement issued Thursday afternoon, Pakistan’s cabinet “expressed its full support for the government to press upon the NATO and the US to frame new parameters of engagements based on mutual respect and the national interests ensuring sovereignty of Pakistan.”

A U.S. official, who spoke on the condition of anonymity to discuss sensitive relations with Pakistan, said that security deals with Pakistan had never included written agreements and that the administration had received no specific new demands. The Pakistani government has long demanded more information on the drone strikes against insurgent groups in Pakistan’s tribal regions.

Speaking at a NATO foreign ministers’ meeting here, Clinton called on Pakistan to continue full cooperation with the United States and coalition forces in Afghanistan as an investigation is conducted into the Nov. 26 airstrike.

She said the joint effort was particularly important in the aftermath of a bombing in Kabul on Tuesday that killed dozens of Afghan Shiites observing a religious holiday participating in a religions observance.

A Pakistan-based group has asserted responsibility for the attack, and Afghan President Hamid Karzai has said the bombing was plotted in Pakistan.

Clinton did not comment on those assertions, but she said that the United States had “expressed to the leaders of Pakistan time and again the importance of our working together to tackle these terrorist groups, because terrorist groups threaten first and foremost Pakistan, as well as Afghanistan and beyond, if left unchecked.”

NATO Secretary General Anders Fogh Rasmussen told reporters here that “the closure of the border crossings is a matter of concern” and repeated his call for Pakistan to accept a coalition invitation to join the investigation into the airstrike.

The investigation is important, Rasmussen said, “partly because we want to know exactly what happened, and partly because we want to learn a lesson” in order to prevent such events in the future.

The United States has expressed condolences to Pakistan but has not responded to Pakistani demands for an apology until the the investigation is completed. “The right response to such a tragic accident,” Rasmussen said, “is to strengthen our cooperation.”

Pakistani presidential spokesman Farhatullah Babar told reporters Thursday that Zardari was “stable, comfortable and resting.”

“Initial tests and investigations have been within normal range,” he said. “The president is recuperating with rest.”

Denyer reported from Islamabad, Pakistan.