KABUL: An Afghan official says the bodies of three border police officers who were abducted in a volatile eastern region have been found by local residents.

Shafiqullah Nang, spokesman for the governor of the eastern Ghazni province, said on Sunday that the three officers were kidnapped by insurgents last week.

He says they were driving from Ghazni to neighboring Paktika province, which borders Pakistan, after a few days' break with their families.

No group immediately claimed responsibility.

The Taliban, as well as criminal gangs, have long operated in the rugged eastern border regions of Afghanistan. Insurgents have stepped up attacks on Afghan security forces in recent months following the conclusion of the U.S. and Nato combat mission at the end of last year.

Moreover, at least 12 people including three Nato contractors were killed Saturday when a suicide car bomber struck a foreign forces convoy, officials said, underlining the precarious security situation in the Afghan capital.

The blast came amid heightened security in Kabul after a wave of bombings earlier this month that killed more than 50 people and wounded hundreds, prompting fury from President Ashraf Ghani who blamed Pakistan for failing to rein in Taliban insurgents.

US-led Nato forces ended their combat mission in Afghanistan in December last year, although a 13,000-strong residual force remains for training and counter-terrorism operations.

The Taliban are stepping up their summer offensive, launched in late April, amid a bitter leadership dispute following the announcement of the death of longtime leader Mullah Omar.