Pakistani President Asif Ali Zardari and Prime Minister Syed Yousuf Raza Gilani Friday strongly condemned the blast at a mosque in the country's northwest, Xinhua reported.
In their messages, Zardari and Gilani said that the government would fight extremists, militants and terrorists and would take all necessary measures to establish the writ of the government.
Zardari said that terrorists committed a horrendous act by carrying out the suicide attack when people were praying in the mosque.
He said that such acts of violence, bomb blasts and terrorism were a serious threat to the country.
Gilani said that the government was committed to bringing peace across the country and addressing the issue of militancy by establishing its writ.
He asked the provincial government to submit a report at the earliest and take measures to nab the perpetrators.
The two leaders in their separate messages to the families of the deceased prayed to Almighty Allah to shower his blessings on the departed souls and grant courage to the bereaved families to bear this irreparable loss.
They also directed the provincial authorities to provide best possible medical care to the injured.
At least 15 persons were killed in a blast at a mosque during prayer time Friday in Upper Dir of Pakistan's northwest, according to local TV reports.
Over 40 people were injured in the blast at the mosque in Hayagai Sharqi in Upper Dir of the North West Frontier Province ( NWFP).
Police have been dispatched towards the blast site.
Witnesses were quoted as saying that a suicide bomber tried to enter the mosque but the people on suspicion stopped him and he blew himself up on the lawn of the mosque at Hayagai Sharqi, a small village in the mountain some 30 kilometers from the Dir city.
Locals people shifted the injured to hospitals in their private cars and on foot as roads to the blast site is in poor condition and narrow for ambulances to reach.
Hayagai Sharqi is stated to be peaceful but the army fighter planes bombed positions of suspected militants at Dug Darra, an area a few kilometers away. Two women were killed in the bombing.
No group claimed responsibility for the blast.