The four were wounded when a suicide bomber's explosive-laden car hit a consulate vehicle in the northwestern city of Peshawar, near Pakistan's semi-autonomous tribal region along the Afghan border.
Local officials say at least two Pakistanis were killed and several people were wounded in the blast.
Earlier, Pakistani officials said the suicide car bomber had killed two Americans. However, the U.S. embassy quickly denied any Americans died.
Police say the bomber's vehicle was loaded with 110 kilograms of explosives.
The bomber struck the vehicle after it left the U.S. consulate and while it was traveling through an area of Peshawar that hosts various international organizations, including the United Nations,
No one has claimed responsibility for the attack.
The Pakistani Taliban, the Afghan Taliban, al-Qaida and affiliated militant groups are entrenched in the tribal regions and take advantage of the porous border to launch attacks against NATO and Afghan forces in Afghanistan. VoA.