A Kenyan,three Somali nationals charged over Mandera attack
Abubakar Salim Kitonga, Maslah Daud Hassan, Musa Daud Hassan and Shukri Abdi Salat were arraigned at the Milimani Law courts where they denied the charges.
Three of them who are Somali nationals faced a separate charge of being in the country illegally.
Two of them were also charged with being in possession of materials, including a mobile phone which they used in instigating the commission of the terrorism act.
The court will rule on their bail application on Wedneday after the prosecution objected to their release, saying they are a flight risk.
36 people were executed on the morning of December 2 last year, when gunmen raided Koromey quarry near the Somalia border, just weeks after 28 others were killed while travelling to Nairobi.