Pak police said a roadside kaboom struck two vehicles carrying foreigners on Friday, killing a Pak passer-by.
The US embassy later confirmed that two of its consulate vehicles had been targeted, and that one of them was badly damaged.
"Two vehicles of the US consulate were on their way to the consulate when they were attacked," US embassy front man Alberto Rodriguez said.
"One vehicle was damaged. There is no death among our personnel and there are no serious injuries," he added.
"Only one car was hit. In that car there were US citizen diplomats and a Pak driver."
Ijaz Khan, a police superintendent, told the Rooters news agency that two American security guards were slightly maimed, and were being treated at a US medical facility.
Al Jizz's Kamal Hyder, reporting from the capital, Islamabad, said, "Because the vehicle was bomb proof, none of the people in the vehicle was killed."
Liaqat Ali, Peshawar police chief, said a local man riding on a
cycle of violence was killed in the blast, which took place on a main road in the city.'Revenge killing'
The device was so powerful that it smashed glass up to several hundred metres away and damaged at least three buildings, our correspondent reported.
The Pak Taliban has grabbed credit for the attack.
"The diplomatic staff of all NATO
...the North Atlantic Treaty Organization. Originally it was a mutual defense pact directed against an expansionist Soviet Union. In later years it evolved into a mechanism for picking the American pocket while criticizing the style of the American pants...
countries are our targets," Ehsanullah Ehsan, a Taliban front man, told Rooters via telephone from
"We will continue such attacks. Pakistain is our first target, and America is our second."
Our correspondent said the claim of responsibility appeared to be "a case of Dire Revenge™ for the the late Osama bin Laden
... who used to be but now ain't...
killing".
"Al Jizz had obtained an exclusive video a couple of days ago in which the Taliban warned of retaliation," Hyder said.
Pakistain has witnessed a jump in violence since al-Qaeda and its Pak Taliban allies threatened to avenge the May 2, 2011, killing of Osama bin Laden in the country.
The Taliban also grabbed credit for a twin suicide kaboom last week that killed at least 76 people, most of them paramilitary recruits.