Four Britons have been kidnapped in Nigeria's southern Delta state, a police official said.

The police are attempting to rescue the four people, who were taken by unidentified gunmen on 13 October, Andrew Aniamaka, a spokesman for the Delta state police, told Reuters.

The British nationals had been doing humanitarian work in the area, according to Agence France-Presse.

The spokesman for Delta state police, Andrew Aniamaka said the kidnapping occurred on 13 October.

“The victims are of British nationality, two of whom are a couple, and have been rendering humanitarian services in the area for a while.

“But unfortunately, they didn’t let the authorities know of their presence in the area all this while.

“There is a militant group that has been operating in the area and we believe they are the ones behind the abduction.

“Immediately the militants struck, they whisked the victims to the interior regions of the creek where we believe they are being held for the past five days.”

This latest kidnapping follows the release of Father Maurizio Pallù, an Italian missionary who was kidnapped by militants on the outskirts of Benin City and taken to a nearby forest.

63-year-old Fr Pallù was released on Tuesday, and told Vatican Radio "the Lord had performed great miracles to keep him alive."

The Foreign and Commonwealth Office said it was aware of the hostage situation in Nigeria but declined to comment further on the case.

The FCO advises against all travel to "riverine areas of Delta State", where the kidnapping occurred.

"If you’re working or travelling in areas where there is a Boko Haram presence, especially in the north-east of Nigeria, you should be aware of the risk of terrorist kidnap", the FCO warns.