A federal judge in Colorado has temporarily blocked the Trump administration from deporting the wife and five children of the Boulder fire-bomb suspect.

Mohamed Sabry Soliman, 45, allegedly injured 12 people aged between 52 and 88 - setting at least one ablaze - at a demonstration honoring the October 7 victims who are still being held hostage by Hamas militants in Gaza.

The horror unfolded during an event organized by Run For Their Lives on Pearl Street Mall in the city's downtown just before 1.30pm local time on Sunday, the first day of the Jewish holiday Shavuot.

The wife and five children of the Egyptian suspect were arrested and taken into custody by agents with ICE and Homeland Security on Tuesday. The legal status and names of his wife and children have not been released.

Soliman's family were being processed for expedited removal, which would allow authorities to rapidly deport them without a hearing in an immigration court.