A multi-agency security team raided an al-Shabaab makeshift camp at Dabalwein in Ijara, Garissa County and killed one militant, police said.
An unknown number of suspects escaped with injuries in the Tuesday evening raid, police aware of the operation said.
The team recovered three AK47 magazines, 90 rounds of ammunition, medicines, foodstuff and personal effects.
They also recovered medical supplies and Improvised Explosive Devices (IED) making materials, police said.
Police said they have heightened operations to pursue the militants in Garissa County and other counties to pre-empt planned attacks in the country.
This is the latest such incident to happen in the area.
Officials say most of the terrorists had set up camps in Garissa which they have been using to launch attacks on motorists and government vehicles.
On November 4, at least two members of the terror group who had been acting as doctors for the group were killed in a raid by police in their camp in Fafi, Garissa County.
Police said the incident happened at a medical camp for the gang in the Hagarso area.
The team on the ground said the two slain al Shabaab 'doctors' had been treating militants injured by security agencies.
Police have since traced some of the recovered medicine to a hospital in Garissa town. The owners of the hospital are under probe.
They however argue they are not in charge or in control of the medicine sold.
The security teams in the area also last month destroyed a logistics base used by al Shabaab militants in Dahun in Fafi, Garissa county and recovered assorted foodstuffs.
The operation recovered rice, sugar and water.
The officers destroyed the food and continued to pursue the terrorists who were using the base.
Police said by the time the team arrived, the terrorists had escaped.
Police say the area is being used as a logistics base for the terrorists who move to attack targets and retreat there.