(CNN) -- Bombings in two restive eastern Afghan provinces killed at least 29 people Wednesday, authorities said.
One strike occurred in Khost city when a suicide bomber on a motorcycle targeted NATO and Afghan security forces. The town is in the province of the same name.
The U.S. Embassy in Kabul and Afghan President Hamid Karzai's office said 17 Afghan civilians were killed and 32 others were injured. The embassy said three members of the NATO-led International Security Force and an Afghan interpreter died in Khost. A Western official told CNN the soldiers are Americans.
"Such disregard for the lives of civilians and soldiers further demonstrates that the Taliban and other insurgents indiscriminately continue their murderous campaign against all, including women and children," the embassy said.
Karzai's office issued a statement strongly condemning the attack. The embassy also condemned the attack and called it "cowardly."
A U.S. official said authorities believe the suicide bomber may have been wearing an explosive vest, which he detonated at a checkpoint. Amir Padshah Mangal, director of the Khost public health department, said three police officers and a child were among those killed.
In Logar province, four children and two women were among eight killed when a vehicle hit a roadside bomb planted by the Taliban, according to a Twitter message from Interior Ministry spokesman Sediq Seddiqi.
CNN's Masoud Popalzai and Nick Paton Walsh contributed to this report from Kabul, Afghanistan, and Barbara Starr contributed from Washington.