An Egyptian court on Monday confirmed the death sentences of 183 supporters of the Muslim Brotherhood who were convicted of playing a role in the killings of 16 policemen in the town of Kardasa in mid-2013.

Reuters reported the verdicts are part of an official crackdown on the Islamists. The Muslim Brotherhood has been outlawed, and in spite of protests by human rights groups, thousands of its supporters have been arrested and put on mass trials.

President Abdel Fattah al-Sisi said the group is a major security threat. Sisi is the army chief who in 2013 toppled Mohamed Mursi, Egypt's first democratically elected head of state. The incidents leading to Monday's death sentences occurred in the midst of clashes that followed Mursi's ouster.

"Today's death sentences are yet another example of the bias of the Egyptian criminal justice system," Hassiba Hadj Sahraoui of Amnesty International said. "These verdicts and sentences must be quashed, and all of those convicted should be given a trial that meets international standards of fairness and excludes the death penalty. Issuing mass death sentences whenever the case involves the killing of police officers now appears to be near-routine policy, regardless of facts and with no attempt to establish individual responsibility."

According to data compiled by Sahraoui's organization, four trials have so far led to death verdicts against 415 individuals accused of killing police officers, but no officials have had to account for the deaths of up to 1,000 protesters in August 2013, CNN noted.

Amnesty International also pointed out that a case against former President Hosni Mubarak, who had close ties to the military, has been dropped. Mubarak had been accused of ordering the slaughter of hundreds of protesters during an uprising toward the end of his longtime rule.

Sisi, meanwhile, warned his countrymen the war against Islamists would be long and tough. In a televised address, the president made no distinction between the Muslim Brotherhood and the ISIS and al-Qaida terror organizations.

ISIS, which dubs itself the "Islamic State," is known for its brutal methods used across the large swaths of land it controls in Syria and Iraq. Al-Qaida, the group once led by Osama bin Laden, became widely known after the Sept. 11, 2001, attacks on the United States.