Published : 24 Mar 2017, 03:19 PM
The call reportedly came from a militant suspect inside the five-storey house at Surma's Shibbari on Friday noon.
Police have been making announcements in loudspeakers, asking the suspects to come out of the house sealed off since 3am Friday.
At one point, naming a female suspect, a policeman said: "Morjina Begum, you have been surrounded from all sides. Surrender peacefully!"
A female was heard replying: "You are walking the path of Satan! We follow Allah!"
Then a male voice followed.
"Why are you wasting time? We don't have much time. Send in the SWAT!"
A SWAT team and bomb-disposal experts from capital Dhaka was headed to the northeastern district, said counter-terror officials.
A grenade was hurled towards CT personnel who had approached the building around 3am, said Sylhet Metropolitan Police Additional Commissioner Rokonuddin.
A couple, Kausar Ali and Morjina Begum, moved into one of the flats on the ground storey of the building with 30 flats, said its owner Ustar Ali.
The man claimed he was an audit official for Pran Foods Ltd.
Police said they found their whereabouts based on information dug out following raids on two hideouts at Sitakunda in Chittagong.