During the Sunday morning operation, the team also recovered AK47 riffle, two magazines, porches and assorted foodstuffs.
Police said three ‘experts’ of assembling the explosives managed to escape.
The team was Sunday afternoon pursuing the gang.
“We hope to get them for justice,” said one official in the team.
Security agencies are appealing to Garissa residents to report any suspected terrorists for action to make the country safe and secure.
This comes weeks after five suspected al Shabaab militants were killed in an operation in Fafi, Garissa County.
Police said four others were arrested in the operation and were taken in for further interrogation. Police said they were cooperating well.
The group was headed for Fafi from a hideout when they were ambushed on March 2.
During the ambush, the team recovered two PKM machine guns, one RPM, six AK47 rifles and a number of Improvised Explosive Devices (IED) making materials.
Mobile phones and SIM cards were also recovered, officials said.
A quick analysis of the phones has so far given important leads on a number of local al Shabaab facilitation network, officials said.
The intelligence-led operation caught the militants by surprise as they crossed into Kenya and establish a temporary camp in Fafi area of Garissa.
Police said the area is being used as a logistics base for the terrorists who move to attack targets and retreat there.
This comes in the wake of reports the terror gang has been sending their members to Kenya in the past month in readiness for an attack.
Police said they have upped their operations in the area to tame the plans for the attacks.
A number of ambushes have happened in the past months which left dozens of security agents dead and injured.
The area is near the Kenya-Somalia border where the militants cross and launch attacks inland.
A major operation is ongoing in the area to address al Shabaab-related attacks, which partly happen due to the proximity to the main Kenya-Somalia border.
The terrorists have been attacking places near the Kenyan border by using guns and explosives leaving dozens dead and many injured.
The recent attacks have forced the government to suspend plans to reopen the Kenya-Somalia border.