The blast happened at a football match in Afghanistan's southeastern Khost province. Earlier, the Taliban had said they would end the partial ceasefire against Afghan security forces and would resume military operations.
A motorbike strapped with explosives killed at least three civilians and injured at least seven others during a football match in Khost province on Monday.
The football match was taking place in Nader Shah Kot district. The Taliban and the government both claim to control parts of the area where the incident took place.
It was not immediately clear who was responsible for the attack.
Monday's incident happened soon after the Taliban had said that they would end the partial truce against Afghan security forces and would resume offensive operations.
"The reduction in violence ... has ended now and our operations will continue as normal," said Taliban spokesman Zabihullah Mujahid. "As per the US-Taliban agreement, our mujahedeen will not attack foreign forces but our operations will continue against the Kabul administration forces."
The US and the Taliban signed a deal aiming to end the conflict in Afghanistan on Saturday, but the Afghan government were not invited to be signatories. Under the terms of the deal, foreign forces will leave Afghanistan within 14 months.
The declaration comes a day after President Ashraf Ghani said he would continue the partial truce — until talks between Afghan officials and the Taliban begin on March 10.
The truce ran for one week as planned, and continued over the weekend. The period saw a dramatic reduction in violence.
Ghani also said on Monday that he was not committed to a key part of the Doha deal involving the release of thousands of Taliban prisoners. The Taliban, meanwhile, said that the prisoner swap was a precondition for talks with Ghani's government.
kmm,ed/msh (AFP, )