Officials and rescue volunteers gather at the bombing site in Peshawar, Pakistan on Monday, Sept. 3, 2012. A car filled with explosives rammed into a U.S. government vehicle on Monday, killing a number of Pakistanis and wounding over a dozen others, police said. (Mohammad Sajjad/AP)

Quick action by Pakistani security forces saved the lives of two American diplomats and two Pakistani U.S. consular staff members whose armored vehicle was attacked by a suicide car-bomber in the northwestern city of Peshawar on Monday, a U.S. Embassy official said.

The attack killed two Pakistanis and wounded 21 local residents, police said. The U.S. government vehicle had left the U.S. Consulate in Peshawar and was traveling through an area of the city that houses the American Club and the missions of several international organizations, including the United Nations, when it was rammed by an explosives-laden car.

The condition of the four victims who worked at the consulate was not known, but the Associated Press quoted a U.S. official in Islamabad as saying that the Americans’ injuries were not life-threatening. The two were not identified.

“I am grateful for the humane professionalism of the local Pakistan security forces who saved the lives of the two American diplomats and the two local staff of [the consulate] by pulling them to safety after their vehicle was attacked,” Richard Hoagland, the charge d’affaires at the U.S. Embassy in Islamabad, said in a statement.

The suicide attack, which appeared targeted at foreigners, renewed concerns about the safety of Westerners working in Pakistan, especially in or near the militant-infested northwestern tribal areas. Peshawar is the capital of Khyber Pakhtunkhwa province, which abuts the semiautonomous tribal belt bordering Afghanistan.

No group asserted responsibility for the attack, but the Pakistani Taliban, allied with al-Qaeda, has in the past vowed to kill foreign nationals and Pakistanis who support Pakistan’s government and the U.S.-led war against the Taliban in Afghanistan.

Although many citizens and local security forces in Peshawar have been killed in insurgent attacks — including 11 who died in a suicide bombing at a marketplace last week — it has been more than two years since Islamic militants successfully targeted a U.S. installation here. The U.S. Consulate was hit with a car-bomb and grenade attack that killed four Pakistanis, security guards among them, in April 2010.

In May last year, a Pakistani bystander was killed when a ­remote-controlled bomb struck two U.S. armored vehicles in the city. In 2008, the chief U.S. consular diplomat survived a gun attack on her armored vehicle.

Secretary of State Hillary Rodham Clinton, in Jakarta, Indonesia, as part of an Asian tour, called Monday’s attack a “cowardly act of suicide bombing and terrorism” and said the United States was praying for the recovery of the American and Pakistani victims.

Muhammad Amir Rana, a Pakistani expert on terrorism, said that terrorist attacks in Pakistan had declined 24 percent in 2010 and 2011 but that the tempo has increased recently.

“The fresh terrorist attacks . . . suggest that the militant groups have been able to regroup and do away with their differences, and now they are again hitting different targets across the country,” he said.

Among those targets are military installations such as the Pakistani air force base that was besieged by suicide attackers last month.

The militants, Rana said, strike “when and where they want to strike.”

Leiby reported from Kabul. Shaiq Hussain in Islamabad contributed to this report.