ISLAMABAD - A bombing in the Afghan capital, Kabul, Wednesday injured at least nine civilians, the first significant incident of violence during the weeklong reduced fighting period agreed to between U.S.-backed Afghan security forces and Taliban insurgents.

Afghan Interior Ministry spokesman Nasrat Rahimi said the improvised explosive device was planted in a motorcycle. He said a woman was among the casualties. Rahimi added an investigation was underway to determine who was behind the attack.

There were no immediate claims of responsibility.

The Taliban swiftly denied its involvement, saying the blast “seems to be the malicious work of intelligence networks trying to create distrust.”

The seven-day reduction in violence pact took effect last Saturday and it is to culminate on the signing of a peace agreement between the United States and the Taliban scheduled for Feb. 29 in Doha, Qatar.

Afghan officials alleged Wednesday insurgents have carried out attacks in several provinces since the partial agreement took effect, killing around two dozen people, mostly security personnel.

There was no immediate reaction from the Taliban to Kabul’s allegations, though the insurgent group insists it had agreed with the U.S. to observe a reduction in violence and not a “cease-fire”.

U.S. officials in the run-up to the reduction agreement, however, had said there were mutually agreed to mechanisms in place to investigate and determine major breaches in order to keep “spoilers” from undermining the Afghan peace process.

U.S. President Donald Trump pauses while speaking during a news conference, Feb. 25, 2020, in New Delhi, India.

On Tuesday, U.S. President Donald Trump said the weeklong truce was largely holding and had brought his administration closer to sealing the pact with the Taliban intended to end the war in Afghanistan.

"We’re pretty close. We will see what’s going on. We have got two days now under our belt without violence, or I guess a minimum of violence, and we’ll see what happens,” Trump told reporters at the end of his trip to India.

Political tensions

Meanwhile, U.S. diplomatic efforts have persuaded Afghan President Ashraf Ghani to postpone his inauguration for his second term until March 9.

Ghani was scheduled to take oath of office Thursday but his main rival, incumbent Afghan Chief Executive Abdullah Abdullah, had also announced to do so to establish a parallel government. Abdullah has rejected the results of the Sept. 28 presidential polls released last week, accusing the national election commission of manipulating the final outcome in favor of the incumbent president.

FILE - U.S. envoy for peace in Afghanistan Zalmay Khalilzad speaks during a debate in Kabul, Afghanistan, April 28, 2019.

U.S. special Afghan reconciliation envoy Zalmay Khalilzad welcomed the decision to delay Ghani’s inauguration, saying it would allow time for necessary consultations to ensure interests of Afghanistan and its people are reflected and preserved by the new government.

"As the electoral process has concluded, President Ghani, as the declared winner, and other leaders should ensure that the new government is inclusive and reflects the aspirations of all Afghans,” Khalilzad stressed.

Speaking on Tuesday, Secretary of State Mike Pompeo noted the partial truce was largely working but reiterated its success would only lead to the signing of the peace agreement on Feb. 29.

Pompeo also urged Afghan leaders to defuse political tensions stemming from the presidential election within their constitutional and legal norms.

"We're on the cusp of enormous, enormous political opportunity. We're not going to let any one small group who has the idea that somehow they can undermine it -- and there are many, many who want to spoil what it is that we have already achieved -- we're not going to let that happen.”

The U.S.-Taliban agreement, if inked on Saturday, would begin a phased withdrawal of American and coalition forces from the country. It would also require the Afghan government and members of other political as well as civil society groups to form a united team to engage in peace negotiations with the Taliban to discuss a permanent nationwide cease-fire and power-sharing in the post-war Afghanistan.