Hundreds of people were coming out of the mosque or waiting for a charity meal when the blast hit, police said, adding that the bomb had been planted inside the building near the town of Nowshera.
Witnesses described scenes of panic, the mosque`s windows and doors blown out by the strength of the explosion and blood sprayed on the building walls.
"I was distributing rice among the devotees when suddenly a huge blast occurred and I remember seeing people running and falling in panic," Suleman Shah, 30, a jeweller, told AFP.
An AFP reporter at the site said: "There were blood marks in the mosque and cooked rice was scattered at some places. The blast had mangled the ceiling fans and all doors and windows of the mosque building were broken."
Taliban and Al-Qaeda-linked militants launch daily attacks across northwest Pakistan and the tribal belt that Washington has branded the most dangerous place on Earth.
More than 4,000 people have died in suicide and bomb attacks across Pakistan since government forces launched an offensive against militants in a mosque in Islamabad in 2007.
The mosque in Friday`s attack is located in a shrine named after Muslim saint Akhund Panju Baba, in Akbar Pura town, on the outskirts of Nowshera.
"The death toll is 11 now as two of the wounded men passed away," Abdul Hameed Afridi, head of the Lady Reading hospital in Peshawar, the main city in the region, told AFP.
The death toll was earlier put at nine.
There was one child among the dead, he said, adding that 21 wounded were being treated at the hospital, four of whom were critical.
Bomb disposal official Hukam Khan said the device weighed about 2.5 kilos (5.5 pounds) and was planted in a shoes rack.
The blast follows a suicide car bombing on Thursday in a densely populated area of Hangu, which lies 150 kilometres (90 miles) south of Peshawar and borders the troubled tribal belt along the Afghan border.
Ten people were killed in that bombing, which coincided with an ambush by militants in the Khyber tribal district killing six policemen, officials said.
The United States wants Pakistan`s army to do more to combat extremists on the border, including by launching a ground offensive in the district of North Waziristan, which it says is home to key Taliban leaders.
The Taliban are engaged in a campaign of violence against security forces in Pakistan, a key ally in the US-led "war against terror", claiming many attacks in revenge for US drone strikes in the tribal areas.
The United States does not officially confirm the controversial missile strikes, which nevertheless take place with Islamabad`s tacit approval. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
