A British man is among four people who have been arrested by the Sudanese government and accused of carrying out "military activities".
The unnamed man was arrested on Saturday alongside Norwegian John Soerboe, 50, a South African man and a South Sudanese man in the oil-rich region of Heglig on the disputed border with South Sudan.
They had all been on a five-day de-mining mission. The area has seen heavy fighting between the two nations over the past few weeks. Sudanese army spokesman Colonel Sawarmi Khalid Saad said the men had military hardware and were driving an armoured vehicle.
The Foreign Office said it was urgently seeking consular access to the arrested Briton.