The United Nations chief on Wednesday expressed grave concern over what he called the “deplorable” conditions of Niger leader Mohamed Bazoum’s detention and called for his release.

Secretary-General Antonio Guterres denounced “the deplorable living conditions that President Bazoum and his family are reported to be living under,” according to a UN statement.

CNN reported Wednesday that Bazoum was being kept isolated and forced to eat dry rice and pasta by the rebels who overthrew him in a coup late last month.

In a series of text messages Bazoum sent to a friend, the president said he had been “deprived of all human contact since Friday”, with no one supplying him food or medicine, the network reported.

Guterres “reiterates his concern over the health and safety of the President and his family and once again calls for his immediate, unconditional release and his reinstatement as Head of State,” the UN chief’s spokesman said in a statement.