“Terrorism is the most important security challenge in the region and the world, which has targeted peace and security of countries and nations without any exceptions,” Iranian Foreign Ministry Spokesman Bahram Qassemi said on Saturday.
He added that the campaign against the vicious phenomenon of terrorism requires enhanced comprehensive efforts by all regional countries and the international community.
The Iranian spokesperson expressed his sympathy with the Pakistani government and the bereaved families of the terrorist attack.
At least 25 people were killed and about 40 others injured after a bomb went off in a mainly Shia Muslims area in northwestern Pakistan on Saturday.
The blast rocked a crowded vegetable market in Parachinar city, the capital of Kurram tribal district near the Afghan border.
The outlawed terrorist group Lashkar-e-Jhangvi (LeJ) claimed responsibility for the attack.
The LeJ militant group has claimed responsibility for some of the most brazen attacks on the Shia community in Pakistan's recent history, including a January 2013 bombing in the southwestern city of Quetta, where over 100 members of the Hazara community were killed.
The notorious militant group, believed to be working with both Daesh and al-Qaeda terrorists, has also turned its guns on government forces in recent years.
Security has been a main issue for the Shias as thousands of them have been killed as a result of militancy and attacks over the past decade.
The Shia community accounts for some 20 percent of Pakistan's 200-million population.