PARACHINAR -- Twin blasts in a market in a mainly Shia area of Pakistan's tribal belt killed 11 people, said authorities.
The market in Parachinar, Kurram Agency, was crowded with shoppers preparing for the Eid ul Fitr festival marking the end of Ramadan.
The first of the two blasts detonated during rush hour, local official Nasrullah Khan told AFP.
"When people rushed to the site... to rescue the wounded, a second blast took place," he said. A second official confirmed the explosions and toll.
"We fear that the death toll will increase," Khan said, adding that no further details were available yet.
Prime Minister Mian Muhammad Nawaz Sharif called for security to be beefed up across the country as he condemned the attack, saying that no Muslim could ever imagine committing such a "horrific" act.
The twin blasts in Parachinar followed a bombing earlier in the day outside the office of the police chief in Quetta, capital of Balochistan Province, that killed at least 13 people.
Investigators said the attack targeted police. It was claimed by both the "Islamic State of Iraq and Syria" (ISIS) Khorasan branch and by Jamatul Ahrar, an offshoot of Tehreek-e-Taliban Pakistan (TTP), according to the SITE monitoring group.
There was no immediate explanation for the dual claims.