Big Gen Ziaul Ahsan, director, National Telecom Monitoring Centre (NTMC), said 1.6 million of them are Banglalink subscribers, 4.6 million Grameenphone, 3.5 million Robi and 250,000 Teletalk users.
As the mobile users left Dhaka, their relatives and house helps also went to villages. So, the total number might be 15 to 20 million people who left the capital, he added.
“If someone of this huge population carries coronavirus, the situation might be devastating," he said.
Also Read: Bangladesh reports first coronavirus death
Bangladesh closed all educational institutions on March 17 and declared a 10-day general holidays from March 26.
The country also suspended public transport including train services to prevent the spread of coronavirus.
Bangladesh on Saturday reported no new coronavirus case or death from the disease in the last 24 hours.
The death toll from novel coronavirus (COVID-19) reached 27,468 globally as of Saturday.
It has so far infected 602,172 people around the world, according to worldometer.