A bomb hidden in a fruit carton ripped through a crowded market on the outskirts of Pakistan’s capital, Islamabad, Wednesday morning, killing 23 people and wounding dozens more, officials said. It was the latest attack to shake the country as government negotiations with the Taliban pick up pace, and was a blow to the government, as such incidents are relatively rare in the capital.

The massive blast sent cartons of produce flying as shoppers were buying daily supplies, and police quickly cordoned off the bloodstained scene littered with debris, shoes and prayer caps.

The market is near a makeshift camp for people displaced from fighting in Pakistan's northwest, as well as refugees from Afghanistan. It is also next to a supermarket that sells food and household items to many of the capital's middle-class families.

No women or children were among the casualties, Al Jazeera's Kamal Hyder reported. There was no immediate claim of responsibility for the blast, which was heard almost 5 miles away, according to Hyder. Yasin Malik, a police official, said approximately 11 pounds of explosives were hidden in a fruit carton.

Government negotiators held direct talks with the Taliban on March 26 at an undisclosed location in one of the country’s tribal areas, and on Saturday the government announced that Pakistan would release 13 Taliban prisoners in order to facilitate the talks. Taliban fighters have also declared a temporary cease-fire.

The Pakistani Taliban in a statement emailed to reporters denied responsibility for the attack, according to The Associated Press, and said they were sticking to a previously agreed cease-fire. However, there was speculation in Pakistan that certain splinter groups among their ranks may be responsible for the attack, leading to questions about whether the group is in full control of various factions that could be behind the attacks, which have continued during the negotiations.

While large-scale bombings are relatively frequent in parts of Pakistan such as the northwestern city of Peshawar or the southern port of Karachi, they are rare in the capital, which is home to diplomats, generals and top government officials.

The symbolism of having such a deadly attack in Islamabad — even in an area on the edge of the city and rarely frequented by its elite — is a blow to the Pakistani government as it tries to increase foreign investment and project an air of security in the capital.

The attack came a day after 13 people were killed and dozens more wounded by a bomb on a train in southwestern Pakistan’s Baluchistan province. The separatist United Baluch Liberation Army claimed responsibility for that incident, saying it was retaliation for a military operation Monday in which Pakistani security forces said they had killed 30 separatists in one of the biggest clashes in months in the gas-rich province.

Al Jazeera and wire services