Police have been allowed 30 days to continue detaining two suspects linked with the ISIS terror group.
The suspects , and were presented in court on Thursday under tight security.
Milimani senior principal magistrate Joyce Gandani granted the request following an application by senior state counsel Duncan Ondimu.
Ondimu made an application requesting more time for police to carry out investigations.
At the hearing, the prosecutor said the suspects were radicalised at the Kangemi mosque, after which they were recruited into Isis by Mohamed Abdi Ali.
Ali, a medical intern, was arrested on April 29 at Wote county hospital in Makueni, while planning a major attack.
His arrest led to the apprehension of his wife Nuseiba Mohammed Haji, in Uganda, and the two suspects in Kangemi.
Haji and her husband are alleged to have been planning to unleash a biological attack using anthrax in Nairobi and Mombasa.
The prosecutor informed the court that during the Kangemi arrest, police recovered various materials used to manufacture Improvised Explosive Devices.
Ondimu alleged that the suspects - Kiguzo Mwangolo and Abubakar Jilo Mohammed - have been planning retaliatory attacks following the Ali's arrest.
He said the suspects intended to use the IEDs to launch terror attacks in Nairobi and Mombasa.
He argued that police needed the additional time to analyse evidence recovered from the suspects' house.
Prosecution said that the two are among the authors of a document that has been circulating online purporting the establishment of Jabha East Africa.
In the document, they declared allegiance to Islamic State of Iraq and Syria leader Abu Bakr Al-Baghdadi.
The court was asked to decline the suspects' bond application, as they are considered to be a flight risk.
Ondimu alleged that Mwangolo and Mohammed have planned to escape the country and travel to Syria or Libya after carrying out their terror attacks.
Police claim that the terror network in Kenya spreads as far as the Coast region, North Rift, Western as well as other countries that include Somalia, Libya, and Syria.
"Investigations in such an offence are intricate and complex requiring diligence. Thus, the fair position would be to strike a balance between the rights of the suspect and the public interest to meet the ends of administration of justice," the magistrate ruled.
Gandani also said the suspects may not suffer prejudice in light of ongoing investigations.
The court went on to issue arrest warrants against two other associates, Ahmed Hish and Farah Dagne, who are medics at Kitale.
The case will be mentioned on June 22.