Some 28 people, who returned to Sylhet from the United Kingdom recently, have tested positive for Covid-19.
Their samples were taken on Sunday and the Covid-19 reports came out positive on Monday.
They were kept at institutional isolation at different hotels in Sylhet city after returning there on 21 January.
After coronavirus detection, they have been admitted to hospitals under government arrangement, said Sylhet Metropolitan Police's Additional Deputy Commissioner BM Ashraf Ullah Taher said on Monday night.
Ashraf said as many as 157 expatriate Bangladeshis came to Sylhet on a Biman Bangladesh Airlines flight from the UK. They were sent to institutional quarantine under the supervision of the army and police.
Initially, all of them tested negative for the virus.
They were scheduled to stay in quarantine for four days. Their samples were again tested on Sunday, a day before they were to leave quarantine.
Among them, 28 samples came out positive, he said.
Of them, 15 were staying at Hotel Nurjahan, five at Britania, four at Holygate, and three at La Rose, and another at Holy Side.
On Monday, 143 more people came from there. They were sent to quarantine after they landed at the Osmani Airport.