One person has been killed in an explosion outside the airport in Peshawar, the capital of Pakistan's North West Frontier Province (NWFP).
There have been a series of blasts in Peshawar in recent months
Two other people were hurt when a bomb exploded in a car parked near the airport's entrance, the police said.
The airport was crowded with a number of flights arriving from and departing for the Middle East, the police said.
There have been a number of bomb attacks in Peshawar recently - one left six people dead.
Tuesday's blast shattered the windows of several cars, reports say.
"It was act of terrorism. We are investigating," senior police officer Malik Saad told Reuters news agency.
Nobody has yet claimed responsibility for the explosion.
Last month, a suspected suicide bomber wounded two policemen and killed himself in Peshawar.
A bomb in a crowded market in the city near the headquarters of Pakistan's border security forces on 20 October killed six people. It was the most serious in a number of unexplained explosions in Peshawar.
Last month, North West Frontier Province was the scene of the deadliest attack by militants on the army since it began operations against pro-Taleban and al-Qaeda fighters close to the Afghan border.
A suicide bomber entered an army training school in the town of Dargai and killed blew himself up, killing 42 soldiers in the process.
Peshawar is close to the border with the tribal region of North Waziristan, known for its militant activities.
Pakistan signed controversial peace accords with militants in the semi-autonomous tribal areas of South Waziristan in April 2004 and in North Waziristan in September 2006.