ISLAMABAD — Two senior army officers and three civilians were killed Wednesday when a suicide bomber ambushed a vehicle carrying security forces near the Pakistani capital, according to a military spokesman.

In the attack in Rawalpindi, next to the capital, Islamabad, the bomber hurled himself at a double-cabin pickup near a railway intersection, killing two lieutenant colonels in the Pakistani army along with the three civilians.

“It is a targeted attack. There is no doubt about it,” said a senior security official who spoke on the condition of anonymity.

Since the pickup did not have the green markings of a military vehicle, the attack raised the possibility the assailants had inside information that it “was carrying army officers,” the security official said.

There was no immediate claim of responsibility, but Pakistani Taliban insurgents have, in the past, repeatedly claimed responsibility for attacks directed at security forces and government installations.