An Afghan child receives treatment after being injured when a bus hit a roadside bomb on the Kandahar-Herat highway, at a hospital in Herat, July 31, 2019. Getty

Kabul, Afghanistan -- A roadside bomb tore through a bus in western Afghanistan on Wednesday, killing at least 34 people, including children, Afghan officials said. Farooq Delaware, spokesman for the governor of Farah province, confirmed the death toll to CBS News and said 17 others were injured in the blast.

Sediq Sediqqi, spokesman for President Ashraf Ghani, gave the same casualty toll and said the bomb had been planted by the Taliban.

"Taliban planted mines kill civilians," Seddiqi said. "A passenger bus hit a roadside bomb, planted by Taliban on Herat-Kandahar highway that resulted in the killing of 34 passengers and wounding 17 others including women and children. All victims are civilians."

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No group claimed responsibility, but the Taliban is the only extremist group known to operate in the region, and they frequently use roadside bombs to target government officials and security forces. The Taliban have kept up a steady tempo of attacks even as they have held several rounds of peace talks with the United States aimed at ending the 18-year war.

The attack came a day after the U.N. mission in Afghanistan released a report saying that most civilian deaths in the first half of the year were caused by Afghan forces and their international allies. The report apparently referred to civilians killed during Afghan and U.S. military operations against insurgents.

The U.N. report said 403 civilians were killed by Afghan forces in the first six months of the year and another 314 by international forces, a total of 717. That's compared to 531 killed by the Taliban, an ISIS affiliate and other militants during the same period. It said 300 of those killed by militants were directly targeted.

The Taliban, who effectively control half the country, have been meeting with U.S. envoy Zalmay Khalilzad and his team since late last year. They appear to be closing in on an agreement whereby American forces would withdraw from Afghanistan in return for guarantees that it would not be used as a launch-pad for international terror attacks.