A Canadian citizen is among the five suspects detained for 30 days in connection with Tuesday's attack on a hotel complex in Kenya's capital, Nairobi.
Four men and a woman stood in the dock at the High Court in Nairobi with their heads bowed.
They are the first suspects to appear in connection with the 19-hour siege at the DusitD2 complex in which 21 people died. But no charges were read out to them.
The director of public prosecution asked for more time to carry out investigations he described as "complex and transnational".
Four of the suspects are Kenyan citizens. The fifth is a Canadian-Somali.
Earlier, police told the BBC they had arrested seven people.
A man who was seen in the company of the militants before the attack is understood to be among those detained, but he was not presented in court on Friday.
Somalia-based Islamist group al-Shabab said it was behind the attack.
Read also: Kenyan forces 'eliminate' hotel attackers