ISLAMABAD, Pakistan — Pakistan lurched between crises on Friday with its military chief, Gen. Ashfaq Parvez Kayani, dismissing talk of a coup and canceling a visit from a top American general, a sign that Pakistani fury at the United States over airstrikes that killed 26 soldiers is far from abating.

Concern has been growing in Pakistan and abroad that the two crises — a political struggle that has pitted civilian officials against the military, and the fraying relations with the United States — are distracting from deeper threats to stability, primarily the faltering economy and the festering Islamist insurgency. The Pakistani Taliban offered a sharp reminder of their potency on Friday, killing one soldier and abducting 15 in an attack on a paramilitary post in the country’s northwest, the police said. The Taliban militants threatened to kill the captives.

But the focus in Pakistan on Friday was talk of a military coup. The rumors were set off a day earlier when the prime minister, Yousaf Raza Gilani, warned publicly of a conspiracy to topple the government. He was careful not to openly accuse the military of plotting a takeover, but he did say that it must answer to the elected government and could not operate as a “state within a state.”

It takes very little to stoke rumors of a coup in Pakistan, where the military has ruled for more than half of the country’s history. Even now, nearly four years after the restoration of democracy, the military remains Pakistan’s dominant institution, and it largely dictates foreign policy and national security matters.