GHAZNI, Afghanistan — A roadside bomb in eastern Afghanistan killed 18 people, including at least five women, who were traveling to a wedding party by minibus, a local government official said on Sunday.

Violence has risen in Afghanistan this year as most foreign combat troops prepare to leave by the end of 2014.

"They were going to attend a wedding party when their minibus was hit by a roadside bomb . . . which killed 18 mostly females, including children," said the governor's spokesman, Shafiq Nang Safai.

The Taliban did not immediately claim responsibility, although it usually denies having a hand in attacks that kill civilians. The local government said, however, it believed the insurgency was to blame.

Improvised explosive devices, like the latest bomb that struck the wedding party, are the single biggest killer in the Afghan conflict, causing over a third of civilian casualties in the first six months of the year, according to a U.N. report.

Although roadside bombs kill civilians almost daily in Afghanistan, Sunday's death toll was unusually high.