Three people have been killed and 11 injured in a motorcycle bomb attack at a football match in eastern Afghanistan, as the Taliban announced an end to a partial truce two days after signing a deal with the US.

The Taliban had agreed to a week-long “reduction of violence” as a confidence-building measure ahead of the agreement signed on Saturday, in which the US pledged that all foreign forces would leave Afghanistan within 14 months, if the Taliban sat down for talks on Afghanistan’s future with government representatives.

The agreed “reduction in violence” expired on Saturday, but US officials had expressed hope it would be prolonged. The Afghan president, Ashraf Ghani, committed to extending it at least until the scheduled start date for intra-Afghan talks, 10 March.

Those talks appeared to be in jeopardy on Monday, as the Kabul government said it had not agreed to the release of 5,000 Taliban prisoners before the negotiations started, an offer made by the US as part of its agreement with the insurgent.

“The Afghan government has not made any commitment to release 5,000 Taliban prisoners before the start of any potential negotiation,” said Sediq Sediqqi, a spokesman for Ghani, adding that the prisoner exchange “cannot be a requisite for talks”, and instead should be part of the negotiations.

A Taliban spokesman said there would be no peace talks without the release of prisoners.

Critics of the US-Taliban deal had warned it had papered over a serious differences on the prisoner issue. It stipulated that up to 5,000 Taliban prisoners would be released by 10 March in exchange for only 1,000 government soldiers held by the insurgents. A parallel agreement the US signed with the Kabul government had only vague language about prisoner exchanges.

“The reduction in violence … has ended now and our operations will continue as normal,” the Taliban spokesman Zabihullah Mujahid told the Agence France Press.

“As per the [US-Taliban] agreement, our mujahideen will not attack foreign forces but our operations will continue against the Kabul administration forces.”

Michael Semple, a former European Union envoy to Afghanistan said that the Taliban saw Saturday’s ceremony, appearing on stage with US officials as a recognised group, as a victory.

“In advance of the agreement, the Taliban leadership, were particularly interested in the theatre of the signing ceremony,” Semple, now a professor at Queen’s University Belfast. “And this in itself was a warning signal.”

There was no immediate claim of responsibility for the attack in Khost.

“A motorcycle rigged with a bomb exploded during a football match,” said Sayed Ahmad Babazai, the Khost police chief.

Abdul Fatah Wakman, the president of the Khost Football Federation, told AFP that the three people killed were brothers.

The commander of US forces in Afghanistan, Gen Scott Miller, issued a statement saying: “The reduction in violence was a confidence builder. We’re very serious about our obligations and we expect the Taliban will be serious about their obligations. The United States has been very clear about our expectations – the violence must remain low.”

The Pentagon leadership in Washington sought to play down the significance of the attack.

“The Taliban is not a monolithic group. There are multiple terrorist organizations operating … so we don’t know exactly who did that yet,” Gen Mark Milley, the chairman of the joint chiefs of staff, said on Monday. “Secondly, I would caution everybody to think that there’s going to be an absolute cessation of violence in Afghanistan … it’s not going to go to zero.”

Laurel Miller, a former acting US special representative for Afghanistan and Pakistan, said the gaps in expectations over the reduction in violence and the prisoner exchange were evident from the moment the agreements were signed on Saturday.

“It’s not surprising that this is controversial for the Afghan government, because … these are prisoners that are held by the Afghan government not by the United States,” said Miller, now the director of the Asia programme at the International Crisis Group. “So, it was a bit … forward-leaning to put the provision on this into a US Taliban deal to which the Afghan government wasn’t part.”

• This article was amended on 12 March 2020. An earlier version had omitted the words “to think” in a quote from Gen Mark Milley. This has been corrected.