ISLAMABAD, Pakistan — A key figure in Pakistan’s new government told two top American envoys today that his country is “no longer a one-man show” and that President Musharraf’s strong-arm tactics against Islamic militants will be scrutinized.

The former prime minister Nawaz Sharif’s comments came as Mr. Musharraf swore in a loyalist of slain opposition leader Benazir Bhutto as the head of a new civilian government.

The deputy secretary of state, John Negroponte, and the assistant secretary of state for South Asia, Richard Boucher, arrived in Islamabad early today, held talks with Mr. Sharif, then visited Mr. Musharraf at the presidential palace. They made no public comment on the talks. The envoys also met with the army chief, General Ashfaq Parvez Kayani, and the chief of the military’s powerful Inter-Services Intelligence, an American Embassy spokeswoman said.

Mr. Sharif, speaking later at a news conference, said he told the envoys that it was “no longer a one-man show in Pakistan” and that the new parliament would decide after exhaustive debate how Pakistan should approach Islamic extremism.

The new coalition formed after February’s elections includes Mr. Sharif’s party. The former prime minister is demanding Mr. Musharraf’s resignation.

Many Pakistanis resent Mr. Musharraf’s support of Washington’s aggressive campaign against Al Qaeda and the Taliban — which operate in Pakistan’s tribal and border regions — claiming it has stoked a bloody backlash.

The security of Pakistan must not be sacrificed in order to protect other countries, Mr. Sharif said.

“It is unacceptable that while giving peace to the world we make our own country a killing field,” he said at a news conference.

“If America wants to see itself clean of terrorism, we also want that our villages and towns should not be bombed,” he said, an apparent reference to recent air strikes near the Afghan border many Pakistanis blame on America and allied forces.

The new civilian rulers have said they would negotiate with some militant groups — an approach that has drawn American criticism in the past.

Yousaf Raza Gilani, who will front the incoming civilian-led administration, took the oath from Mr. Musharraf today at a stiff ceremony in Islamabad.

Seated side-by-side on a raised dais and flanked by two honor guards with white and gold-braided uniform, Mr. Gilani followed Mr. Musharraf’s lead in reading the oath of office.

Members of Mr. Gilani’s party chanted “Long Live Bhutto!” after the formalities were complete.

Mr. Musharraf betrayed no emotion during the ceremony but gave Mr. Gilani a firm handshake and chatted amiably with him as they headed for refreshments in the presidential palace.

“I congratulate Yousaf Raza Gilani and my cooperation will always remain with him,” Mr. Musharraf told state-run television afterward.

Mr. Gilani, leading a civilian government after eight years of military rule, appealed for national unity to tackle the crises facing Pakistan, particularly economic problems.

“We have to give supremacy to the parliament so that we can jointly take the country out of these crises,” he said.

An editor with Dawn newspaper, Zaffar Abbas, said the visit of the high-profile American delegation on the same day as the swearing-in was badly timed.

Their presence on the day when the new prime minister was inducted would signal to both Islamic extremists and moderates that “here are the Americans, right here in Islamabad, meeting with senior politicians in the new government, trying to dictate terms,” Mr. Abbas said.

A State Department spokesman, Sean McCormack, told reporters in Washington the trip gives Messrs. Boucher and Negroponte an opportunity to meet with Pakistan’s new government.

He did not provide details of the meetings but said America is interested in broad economic and political reform in Pakistan and a strong role for the nation in fighting extremists.

The Bush administration has been a staunch supporter of Mr. Musharraf, who has deployed troops along the Afghan border and helped kill or capture a string of Al Qaeda leaders. But in recent weeks Washington has started to put some discreet distance between itself and a once “indispensable” ally in the war on terror.

Today, Mr. McCormack called Mr. Musharraf “an important person” in Pakistan’s political world and a good friend and ally of America.

Parliament elected Mr. Gilani as premier yesterday, five weeks after the opposition swept parliamentary elections supposed to return Pakistan to democracy after Mr. Musharraf’s rule. Bhutto’s party, now led by her widower, Asif Ali Zardari, earned the most votes.

In a move that heralds a showdown with the former army strongman, Mr. Gilani immediately prompted authorities to release senior judges who were ousted and put under house arrest when Mr. Musharraf imposed emergency rule last year.

Today, a steady stream of well-wishers, many carrying bouquets of flowers, came to pay respects to the house of the deposed Chief Justice, Iftikhar Mohammed Chaudhry.

Mr. Chaudhry plans to address bar associations around the country, said a senior lawyer who has led protests against the crackdown on the judiciary, Aitzaz Ahsan,.

Washington has voiced no support for the incoming government’s promise to restore the ousted judges — a move which would make it very hard for Mr. Musharraf to continue in office.