The kidnappers of a team building a school in Afghanistan released three men on Monday, a day after their capture, but were holding two including an engineer contracted to a foreign group, the UN said.
The five Afghanis were kidnapped on Sunday in the eastern province of Paktia's Zurmat district where Taliban had reportedly warned foreign organisations they should not work.
Police said the abductors were from the extremist Taliban movement, which has in the past abducted several Afghans and foreigners working on reconstruction projects, and killed some of them.
One of the men still being held by the kidnappers was contracted to the International Organisation for Migration, a UN spokesman said. The other was the head of a local construction company, spokesman Aleem Siddique said.
Three daily labourers abducted with them had been released and were with tribal elders in the region, he told AFP. "They said they were kept blindfolded and in captivity since yesterday," he said.
Police said earlier four men were abducted by the Taliban.
The Taliban, which began an insurgency after being removed from government in 2001, target their insurgency at Afghan and foreign troops as well as UN and non-government organisation workers and government employees.
On Friday a 36-year-old Italian photojournalist, Gabriele Torsello, was freed after three weeks in captivity in the volatile south of the country.
His abductors had initially claimed to be from the Taliban but main spokesmen for the movement said they were not involved and reportedly even called for his release.
South and south-eastern Afghanistan have been hard hit by a wave of violence linked to the Taliban. Al-Qaeda is also said to have a hand in the bloodshed, as are other extremist factions.