An Indian and a Nepalese national kidnapped a month ago were set free by their captors and walked for hours to reach their base in western Afghanistan on Sunday, one of them told AFP.

The intelligence chief of the western province of Herat said earlier that the pair, kidnapped April 21, had been freed in an overnight operation, but this was rejected by Indian national Muhammad Naeem.

Naeem told AFP the kidnappers had told him and his Nepalese colleague to leave late Saturday without giving any explanation.

He said they had walked eight hours to reach a police camp in Adraskan district, where they had been based before they were abducted.

"Last night we started and came here," he said. "There was no operation."

Naeem said he did not know who the kidnappers were or what their motive was.

The Indian said he and Nepali Gurong Karna Bahudur, about 55, had not been treated badly but found the conditions of their captivity difficult, including having to sleep on the floor and survive on only Afghan bread and tea.

The Indian logistics officer said he was in good health but had lost some weight.

Herat provincial intelligence chief Habibullah Habib told AFP earlier that his forces had located the place where the two were held and staged a raid overnight.

He said the pair had briefly been taken to the Shindand, a nearby district that has seen much Taliban activity, before being brought back.

"The operation was in Adraskan," he said, refusing to give details.

A man arrested two days after the kidnapping had confessed to his involvement, Habib said.

In Kabul, a spokesman for the national intelligence department also refused to give details of the release. "I can only confirm that they have been freed from the claws of the kidnappers," said Sayed Ansary.

The men had undergone medical check-ups after arriving back at base and preparations were being made to fly them home, said Sayed Ibrar Hashimi, head of security at the camp.

The men were both working for an Afghan company supplying police training camps, he said.

The pair went missing April 21 while travelling in Adraskan, which borders Iran. Their Afghan driver told authorities that gunmen had taken the foreigners but freed him.

The extremist Taliban militia, blamed for scores of such abductions over the past years, never claimed responsibility.

There has been a spike in recent months in the number of kidnappings by criminal gangs who want to extort ransoms and sometimes kill or maim their victims, who are most often Afghans, including children of prominent families.

Hashimi said he did not believe any ransom was paid to free the Indian and Nepalese and their release was due to efforts of the intelligence agency, the National Directorate of Security.

"Both are physically fit and mentally fit... as a whole they are feeling well," he said.

Afghanistan is trying to rebuild from the ruins of war that remained after a US-led invasion in late 2001 ended the Taliban's five-year grip on power.

The international community has sent billions of dollars in aid and expertise and thousands of troops, weapons and equipment.

But a Taliban-led insurgency, which also sees "jihadists" from other countries on the battlefield, has been able to grow as other problems have mounted, including an explosion in crime, and in opium and heroin production.