The novel coronavirus has been detected in one of the camps in southern Bangladesh that are home to more than a million Rohingya refugees, officials said, as humanitarian groups warned that the infection could devastate the crowded settlement, according to Reuters.

It was the first confirmed case in the camps, which are more densely populated than most crowded cities on earth.

“Today they have been taken to an isolation centre after they tested positive,” Mahbub Alam Talukder, the Refugee Relief and Repatriation Commissioner, told Reuters by phone.

The other patient was from the “host population”, a term usually used to refer to locals living outside the camps, the UN spokeswoman said.