LAHORE, Pakistan — Two suicide bombers blew themselves up at a naval college today, killing four people and underlining the security challenge facing the winners of Pakistan’s landmark elections.

The bombers rode up to the gate of the college’s parking lot on a motorcycle. The passenger dismounted and destroyed the gate with a bomb, allowing his accomplice to ride inside and unleash a much more powerful blast, the police chief in the eastern city of Lahore, Malik Iqbal, said.

A 23-year-old chauffeur, Muhammad Safdar, said he had dropped off an officer at the college and was sitting in the cafeteria when he heard the first blast and rushed outside.

“There was smoke and vehicles on fire … Several people were lying on the ground injured and crying for help, but I, too, was injured as something hit me in the neck,” he told reporters.

Pakistan Navy War College, which trains senior naval officials from Pakistan and other countries, is the latest target in a bombing campaign that has killed hundreds in recent months and relented only briefly during the February 18 parliamentary elections.

In Washington, a State Department spokesman, Tom Casey, told reporters America condemned the attack and offered its sympathies to the victims and their families.

Terrorists in Pakistan “are willing to use any and all” techniques to carry out their objectives, he said. Continuing attacks show the importance of America working with the government to fight extremism, he said. “We want to be able to work well with the new Pakistani government once it’s formed,” Mr. Casey said.

The co-chairman of the party expected to lead the new government, Asif Ali Zardari, called the bombing as “inhuman, barbaric and most despicable.”

Pakistanis must unite against “conspirators and extremists,” the widower of opposition leader Benazir Bhutto, who was assassinated in a gun and suicide bomb attack in December, Mr. Zardari, said.

President Musharraf said the government “would not be cowed down by such acts,” vowing to “continue the fight against extremism and terrorism,” the state-run Associated Press of Pakistan news agency reported.

The four dead and 14 wounded were all employees of the college, Mr. Iqbal told reporters. None were senior military officials, he said.

The police chief said it was too early to speculate about who was responsible for the attack.

On Friday, suicide blasts killed 40 people at a funeral for a slain police official in the restive Swat Valley. About 40 tribal elders died in another suicide attack Sunday as they discussed setting up a militia force to combat militants near the Afghan border.

The violence increases the pressure on moderate, pro-Western parties who triumphed in the vote to form a government and review government strategy against the militants.

However, the parties of Bhutto and another former prime minister, Nawaz Sharif, have said their priority is reducing the sweeping powers accumulated by Mr. Musharraf since he seized power in a 1999 coup.

The chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, today was making his second visit to Pakistan in a month, emphasizing concern in Washington at the growing strength of Al Qaeda and Taliban militants.

Admiral Mullen and Mr. Musharraf, who has been a key ally in the American-led war on terror, discussed the “regional security situation and the measures being taken to address it,” the news agency said.

Admiral Mullen also conferred with General Ashfaq Parvez Kayani, who replaced Mr. Musharraf as army chief in November as part of the country’s transition back to democracy after eight years of military rule.

Details of the talks were not released, but Admiral Mullen was expected to discuss American military assistance including plans to send American counterinsurgency experts to Pakistan this year to help train a paramilitary force on the front line of the battle with militants near the Afghan border.