"The man, who was speaking, said that a suicide squad will attack the court today," Rashid said.
After the threat, security was immediately heightened at the court premises.
Chittagong police have said that apart from tightening security, an additional six platoons of police have been deployed in the court area.
Searches are being conducted at the court premises and in nearby areas, a police official said.
The phone from which the call was made has been switched off since the threat call was received, the official added.