The main gate at the prison in Guantanamo at the US Guantanamo Naval Base. (Photo: AFP/ VNA)

Blinken, on a visit to Paris, noted that only about 40 prisoners were left but said the issue remained “complicated”.

The prison was set up under president George W. Bush for suspects captured around the world on the understanding they would not be entitled to the constitutional protections to due process guaranteed on US soil.