Gunmen have shot and killed five people, including two police officers, in Elwak town.
Also killed in the morning attack are three civilians, according to Mandera South police chief Charles Chacha.
Mr Chacha on Friday told the Nation that the unknown attackers arrived at the bank in a Toyota Probox and opened fire, shooting indiscriminately.
Mandera County Commissioner Fredrick Shisia confirmed the 9.30am incident.
“A Toyota probox without number plate approached Equity Bank and the occupants started spraying the bank premises with bullets,” he said.
Mr Shisia said “a good number of civilians” around the bank were injured in the incident but he was yet to confirm the exact number.
“The probox sped off towards Elwak, Somalia, and our officers are pursuing it with the assistance of friendly forces in Somalia,” he said.
It is a difference of 10 kilometers between Elwak Somalia and Elwak Kenya and there is free movement of people.
“We are trying our best to intercept the vehicle with the help of Somalia forces but the motive of the attack is not known,” he said.
According to Mr Shisia, the increase in terror incidents in Mandera could be due to killing of two top commanders of Al-Shabaab from Elwak town.
“We have unconfirmed reports that these incidents are due to killing of their commanders in two different incidents by our security officers,” he said.
In a separate incident, an improvised explosive devise narrowly missed to hit a vehicle at Qurqura area in Mandera County.
The Toyata Hilux was heading to Mandera from Elwak and the explosive went off just before the vehicle ran over it at 8.30am.
Mr Shisia said the IED smashed the windows of the vehicle and the driver drove to Lafey Police Station where he reported the incident.
“We want those using that road to be careful and report any suspicious activity to security agents and avoid places with disturbance,” he said.
Mr Shisia said the new phenomena of attacking civilian vehicles was being investigated.