Afghan television aired yesterday a clip of a blindfolded man said to be a kidnapped Bangladeshi national and said his abductors threatened to cut off some of his limbs unless a ransom was paid.

The short video broadcast on Private Tolo TV showed a man said to be development worker Nurul Islam, who was abducted nine days ago in Logar province, 50 kilometres (30 miles) south of Kabul.

He was standing in front of a rock wearing jeans, his eyes covered in a blindfold. He appeared to be talking but his voice could not be heard on the broadcast.

There was no way to independently confirm it was 39-year-old Islam. His employer, the Bangladesh Rural Advancement Committee, was not immediately available to comment.

Tolo said the kidnappers had threatened to cut off one of the man's legs and an arm unless they received 500,000 dollars.

A Tolo staffer told AFP the video and the message were delivered to the station by unknown men. They did not say they were with the insurgent Taliban movement, which has been behind several abductions in Afghanistan.

Police in Logar, where Islam was seized from his office in broad daylight on September 15, said four people had been arrested in connection with the kidnapping.

"Our search continues for him and we believe he might have been moved out of Logar and taken to Pakistan," provincial police chief Ghulam Mustafa told AFP.

Crime has soared in Afghanistan since the fall of the Taliban government in 2001, with regular reports of Afghans kidnapped by ransom-seekers.

A string of Afghans and foreign nationals have also been abducted by Taliban insurgents. They have tried to use them to barter with the government and have killed several of their hostages -- mostly Afghans.