An Egyptian court sentenced 21 defendants to death on charges that included adhering to "takfiri" thought, membership in a "terrorist organisation", possession of weapons and explosives and planning attacks on public and private property.
In the trial dubbed in the media as "the Damietta terrorist cell", 28 men, including 16 of those who received death sentences, were sentenced in absentia, Reuters reported.
The Cairo Criminal Court sentenced four defendants to life and three to 15 years in jail without chance of parole, judicial sources said.
Defendants have the right to appeal the decision.
In December, the Cairo Criminal Court referred the files of 19 defendants to the Grand Mufti seeking his approval of death sentences issued against them.
Egypt has recently witnessed an increase in the issuance of the death penalty as a result of authorities' heavy handed response to opposition and dissent. Officials say they have been tackling an increase in terrorist activists which requires a strong position to be taken.
In September last year, President Abdel Fattah Al-Sisi told US officials in New York that human rights should not be judged from a Western perspective, arguing that Egypt had taken numerous measures to ensure the economic and social wellbeing of its citizens.