ISLAMABAD, Pakistan – President Gen. Pervez Musharraf’s government dismissed a last-ditch U.S. call to end emergency rule, leaving the Bush administration with limited options Sunday in steering its nuclear-armed ally back toward democracy.

Pakistan said U.S. Deputy Secretary of State John Negroponte brought no new proposals on a make-or-break visit, and received no assurances after urging Musharraf to restore the constitution and free thousands of political opponents.

“This is nothing new,” Foreign Ministry spokesman Mohammed Sadiq told The Associated Press. “The U.S. has been saying this for many days. He (Negroponte) has said that same thing. He has reiterated it.”

Locked in a battle with increasingly powerful Islamist militants, Pakistan is seen as a key front in the war on terror. U.S. officials are clearly fearful that the emergency rule imposed more than two weeks ago could lead to a potentially destabilizing round of political turmoil.

In an early morning news conference before departing Pakistan, Negroponte said he hoped that the president listened to his appeal to end a crackdown on opponents before legislative elections scheduled for January.

“I urged the government to stop such actions, lift the state of emergency and release all political detainees,” Negroponte told reporters at the U.S. Embassy. “Emergency rule is not compatible with free, fair and credible elections.”

But Musharraf has appeared intent on setting his own pace despite warnings from Washington, which has been hesitant to match criticism with actions such as cutting military aid.

Militant gains have raised U.S. concerns about Pakistan’s ability to combat militancy and flush out remnants of al-Qaida and the Taliban believed to be sheltering in the country’s rugged northwestern tribal areas.

Pakistani army helicopter gunships strafed militant positions in the northwest on Sunday, hitting a valley where fighters loyal to a pro-Taliban cleric have been battling security forces for months, the army said.

Soldiers also fired artillery and mortar shells at militants in Swat, inflicting “many casualties,” the army said. It did not offer any specific casualty figures.

Fighting in Swat, a former tourist destination about 100 miles northwest of Islamabad, has turned parts of the region into a no-go zone for journalists, and the army claims could not be independently verified. The rebels could not be reached comment.

Fighters loyal to Maulana Fazlullah, a rebel cleric who wants to impose Islamic rule, have steadily advanced down the Swat valley since July, taking over towns and driving back government forces.

On Saturday, a top general said 15,000 troops were massed for a major offensive against the insurgents, and the military said that between 35 and 40 rebels had been killed in attacks by army helicopter gunships a day earlier, bringing the total number of rebels killed in the past week to more than 100.

Elsewhere in the northwest, rival Sunni and Shiite Muslims battled Sunday in a town where three days of sectarian violence has left 91 people dead, officials said.

Both sides fired mortars and other heavy weapons at each other in the town of Parachinar late Saturday and early Sunday, targeting residential areas and hitting mosques, an intelligence official said. He spoke on condition of anonymity because he was not authorized to speak to the media.

Plumes of smoke were seen billowing from two Sunni neighborhoods in the town early Sunday, the official said.

In a bid to quell the violence, the military said it was deploying an unspecified number of soldiers and members and Pakistan’s Frontier Constabulary paramilitary force to Parachinar.

Musharraf has insisted he would only lift the emergency if the national security situation improved, and strongly hinted that such a move was unlikely before parliamentary elections scheduled to be held by Jan. 9. The opposition has called that position preposterous, saying a free and fair vote could never be held while thousands of opponents were behind bars and political parties were denied the right to assemble.

Sadiq insisted the government was taking all necessary steps to hold a fair election.

Despite Musharraf’s apparent intransigence, Negroponte would not characterize his trip as a failure.

“In diplomacy, as you know, we don’t get instant replies when we have these kinds of dialogue,” he said. “I’m sure the president is seriously considering the exchange we had.”

Senior Bush Administration officials have said publicly that they have no plans to cut off the billions of dollars in military aid that Pakistan receives each year.

Musharraf has said he would step down as army chief by the end of the month, but has insisted that he will serve out a five-year term as civilian president. He won the extra term in an October vote in parliament. The Supreme Court was set to rule on whether the vote was constitutional when Musharraf declared the emergency on Nov. 3, effectively purging the court. In addition, some 2,500 opponents have been jailed and independent TV stations taken off the air.

Musharraf has defended the moves, saying they are necessary as his forces struggle to combat an increasingly virulent Islamic insurgency. But opponents note that the vast majority of those targeted in the crackdown have been pro-Western moderates, human rights activists, lawyers and journalists.

Negroponte met for more than two hours Saturday with Musharraf and Pakistan’s deputy army commander, Gen. Ashfaq Kayani, as well as other leaders. He also spoke by phone with former Prime Minister Benazir Bhutto, who returned to Pakistan last month hoping to work out a power-sharing deal with Musharraf but has ended up becoming one of the leading voices calling for his resignation.

Negroponte urged the two on Sunday to restart talks and ease “the atmosphere of brinkmanship and political confrontation.”

“If steps were taken by both sides to move back toward the kind of reconciliation discussions they were having recently, we think that would be very positive and could help improve the political environment,” he said.

Bhutto told CNN’s “Late Edition” that: “I believe Mr. Negroponte did the right thing in asking General Musharraf to lift the gags on the media, to release the thousands of opposition and human rights leaders, as well as to retire as chief of army staff … We just wonder how we can have fair elections when so many people are under arrest and the media is gagged.”

Though measured in his comments, Negroponte expressed some impatience with Musharraf, saying he hoped to see more steps toward democracy soon. “There remain some other issues that are yet to be considered, or yet to be undertaken,” he said, without going into detail.

Associated Press reporters Matthew Rosenberg and Sadaqat Jan in Islamabad contributed to this report.