Updated

A growing hunger strike among Guantanamo Bay detainees has sparked concern within the Red Cross, who is sending a doctor to the facility to address the “tensions.”

Pentagon spokesman Maj Jeff Pool told the BBC that 31 of 166 detainees at the facility in Cuba are now on a hunger strike, up from 21 last week.

Human rights groups and the prisoners’ lawyers say the strike -- which began weeks ago -- is occurring because detainees are feeling uncertain about their future.

"We see a clear link between that and their emotional state," added Simon Schorno, spokesman of the International Committee of the Red Cross.

On Wednesday, White House Deputy Press Secretary Josh Earnest said that President Barack Obama’s team is closely monitoring the hunger strike and remain committed to closing Guantanamo Bay.

Click to read more from the BBC.