The attackers shot dead some victims and stabbed others with knives, a regional police chief told the AFP news agency.
Four people were killed instantly in the attack and three others died at a hospital in the Balukhali camp, the agency reported.
Police did not say how many people were wounded.
“We arrested one attacker immediately after the incident,” Shihab Kaisar Khan, regional chief for an armed police battalion, told reporters.
The man was found with a gun, six rounds of ammunition and a knife, he added.
The killings came amid mounting tensions after Rohingya community leader Mohibullah was shot dead outside his office in the sprawling camps three weeks ago.
Following the killing, Home Minister Asaduzzaman Khan Kamal said “arrangements will be made to increase security” at the Rohingya camps in the coastal Cox’s Bazar district.
“Manpower and logistical support of law enforcement agencies … will be provided to enhance security,” said Kamal.
The minister noted surveillance and border patrols would be stepped up to curb the entry and sale of drugs in Rohingya camps. Surveillance on the Naf River, the only transboundary river between Bangladesh and Myanmar, will be strengthened, he added.
Kamal stated construction of barbed wire fences in the camps is in the final stages and there are several watchtowers across the camps to monitor movements.
Rohingya activists say there is a mounting “climate of fear” in the camps, with some of them forced to go into hiding since Mohibullah’s killing.
Last December, Bangladesh, which hosts nearly a million Rohingya, relocated more than 20,000 refugees to Bhasan Char island. It plans to relocate an additional 80,000 people after signing an agreement with the United Nations to facilitate refugees on the remote island.
Bhasan Char is located 50km (31 miles) off Bangladesh’s southwestern coast and nearly 193km (120 miles) south of the capital, Dhaka, where the government has constructed 1,400 cluster houses, each made up of 16 rooms.
