This came as it emerged that Sheikh Ali Bajero and Sheikh Binluli Abdulrazak were arrested on Monday night by the anti-terrorism police. (Read: Two arrested in terror claims)
Mr Bajero was arrested shortly after evening prayers at Brakani Mosque, while Mr Abdulrazak was detained when he went to visit Mr Bajero at the Coast provincial police headquarters.
This was the second time Mr Bajero was being held over links with the Somali insurgents. He was previously arrested for allegedly recording a video urging young men to join al Shabaab.
Kenyan security agents are concerned about the increasing number of youth being recruited to join al Shabaab, which is opposed to the Transitional Federal Government in Somalia.
Police spokesman Mr Eric Kiraithe, however, declined to comment on the investigations, saying they were sensitive.
"I don't wish to comment on terrorism investigations at the moment," Mr Kiraithe said on Wednesday.
This came as it emerged that two men had been arrested over alleged recruitment of youths to join the insurgents in Somalia.
Last month, police commissioner Mathew Iteere called in the Federal Bureau of Investigations (FBI) to probe two grenade attacks that killed three police officers in Nairobi's Eastleigh and Kasarani areas.
The detectives have been combing the region since the July 11 Kampala bombings which left 76 football fans dead. (Read: Alert as terrorists bomb Kampala)
Al Shabaab later claimed responsibility for the attack. Several Kenyans are in detention in Uganda over the blasts.