The hostage, Philip Walton, described as the son of a missionary living in Niger, was abducted Monday night on the outskirts of Massalata, a village about 10 kilometres (six miles) from the border with Nigeria.

"I confirm the American hostage was released last night," minister Issoufou Katambe said, without giving details of the circumstances of the release or the hostage's whereabouts.

Local officials had said this week that the kidnappers had called the man's father to demand a ransom, though the family did not confirm this.

Walton had been living in Massalata with his wife and child for two years, according to his father, who himself has been in Niger for nearly 30 years.

Niger lies in the heart of the vast Sahel region, which is struggling with a jihadist insurgency that has claimed thousands of lives and driven hundreds of thousands from their homes.