Four members of law enforcement agencies were left injured in two of the incidents
Three people have been killed in reported gunfights in Natore, Cox's Bazar, and Magura districts.
The incidents occurred early Friday.
In Magura, a suspected robber was killed in a reported gunfight with another gang of robbers in Boruinatoil village.
The deceased was identified as Mintu Kazi, 42, son of Fayez Kazi of Lohagora upazila in Narail, reports UNB.
Superintendent of Police (SP) Torikul Islam said Mintu died during the gunfight that occurred between two groups of robbers over sharing money around 2:30 am.
Police recovered the body in the morning and sent it to Sadar Hospital morgue for autopsy, he said.
Mintu was an accused in 12 cases filed with different police stations, he added.
In Natore, a suspected criminal was killed in a reported gunfight with police in Gurudaspur upazila.
The deceased was identified as Hanif Bepari, an accused in the murder case of Monowara Begum, wife of a Freedom Fighter.
Gurudaspur police station Officer-in-Charge (OC) Mohjaharul Islam said when they conducted a drive at Gurudaspur area around 2:45am along with Hanif.
His accomplices fired gunshots on police, prompting them to fire back in self defence which triggered the gunfight.
Hanif died on the spot while two cops were injured.
They also seized five rounds of bullets, a pistol and a pipe gun from the spot.
Police arrested Hanif from Merul Badda area of the capital on Wednesday night after Monowara Begum was hacked to death on January 16.
In Cox's Bazar, an unknown Rohingya man has been killed in a reported gunfight with Border Guard Bangladesh (BGB) in Hnila union of Teknaf upazila.
The incident happened near Jadimora mosque beside Naf River around 4am.
Teknaf BGB 2 Captain Lt Col Mohammad Faisal Khan said: "Our team was patrolling in the area while few men were crossing with sacks on their heads. When we tried to stop them they opened fire at us triggering a gunfight.
"Later, the man was rescued from the spot with bullet injuries and the rest managed to flee. He was rushed to Teknaf Health Complex and then taken to Cox's Bazar Sadar Hospital where on-duty doctors declared him death."
On primary investigation the man said he is from Myanmar and lives in Thaing Khali camp in Ukhia. BGB claims him to be a drug trader.
The body has been sent to the hospital's morgue for autopsy and the incident left two BGB men injured, said the BGB official.
A case has been filed with Teknaf police station and BGB is working to know his identification, he added.
BGB has also recovered a local made firearm and 130,000 yaba pills from the spot.