Twelve Afghan were killed in two separate attacks, officials said Tuesday, dpa reported.
Six engineers working for the Rural Ministry, kidnapped by Taliban insurgents late Sunday, "were found dead today in Gulran district," said a police officer in the western province of Herat.
"The Taliban killed these people after negotiations with the local government and tribal elders for their release failed," the officer told dpa, asking not to be named.
It was not clear what te militants' demands had been, the police officer said.
Officials in the Ministry of Rural Rehabilitation and Development said five of the victims worked for the World Bank-funded National Solidarity Programme, and another was a ministry employee.
In the eastern province of Paktiya, another six civilians were found dead early Tuesday, the governor's spokesman said.
"The bodies of six people, all civilians, were found this morning in Zormat district," Rohullah Samoon told dpa, adding they had been shot dead, and the authorities were investigating.