Thirty-four people were killed and 100 wounded in a blast during Friday prayers at a mosque in Pakistan’s Khyber Agency, a government official said.

The mosque had about 300 people when the blast went off, officials said.

One worshipper said the blast was so loud, he passed out.

“When I stood up, I saw dead bodies and injured people everywhere,” Hikmat Ullah Afridi said.

Officials were still trying to get more information on the blast in the village of Ghondi, said Mutahir Zaib, a senior government official of Khyber Agency.

Khyber Agency is a one of the seven districts of the tribal region in northwest Pakistan bordering Afghanistan.

CNN’s Nasir Habib contributed to this report.