A group of armed men attacked and vandalised a businessman’s under-construction 10-storey building and exploded cocktails in the South Pahartali area of Chattogram on Sunday, allegedly after failing to extort him to the tune Tk 20 lakh.

No one has been arrested in connection with the incident so far, which has sparked panic among residents.

The incident occurred in a residential area near the Boro Dighirpar-Bhatiari Link Road under Ward No. 1 of Chattogram City Corporation.

According to locals and police, around 8-10 masked armed men arrived at the site in a tempo in the morning and entered the under-construction building while workers were busy there.

The attackers allegedly beat up several workers and vandalised doors, windows and other parts of the building.

At one time, they attacked construction worker Hasan Saki with a kirich, injuring him. Several other workers, including the building’s security guard, were also assaulted.

Before leaving, the attackers exploded three cocktails and fled the area.

The businessman, Mohammad Jasim Uddin, said he runs a wholesale rice and sugar business in the Boro Dighirpar area of Hathazari and recently started constructing the 10-storey building there.

He said he had been receiving calls from foreign numbers demanding Tk 20 lakh in extortion over the past month.

“The callers remained silent for a few days after people protested against an attack on an internet company in the city. But they started demanding the money again over the past week,” he said.

Jasim said he had informed police about the extortion threats and would file a case over Sunday’s attack.

However, he could not identify who was making the extortion demands.

Kazi Md Tarek Aziz, additional superintendent of police (Hathazari Circle), said the attack was captured on CCTV footage.

“Police are analysing the footage to identify the attackers. Drives are underway to arrest them,” he said.