A wave of mass sentences in Egypt, including hundreds sentenced to death this week after a rushed mass trial, has sparked charges that military-installed authorities are using the judiciary as a blunt tool of repression.

The sentences handed out Monday to nearly 700 supporters of ousted Islamist president Mohammed Morsi -- after only one hearing -- fed international outrage after a similar verdict last month, although most of the previous batch of sentences were commuted to life imprisonment.

Iran on Tuesday warned that the 683 death sentences handed down by an Egyptian court to suspected Islamists could add to a deteriorating situation in the country.

The verdicts passed on Monday in Cairo amid a crackdown on supporters of ousted Islamist president Mohammed Morsi were condemned by the United States and the United Nations.

The United Nations and Washington have condemned death sentences handed to 683 alleged Islamists including Muslim Brotherhood leader Mohamed Badie in an Egyptian court Monday after a brief hearing.

The court in the southern province of Minya sparked an international outcry with its initial sentencing last month, amid an extensive crackdown on supporters of ousted Islamist president Mohamed Morsi.

Egypt-U.S. relations remain difficult and "honest" talks are needed to put them back on track, Egyptian Foreign Minister Nabil Fahmy warned Monday, even as the White House blasted a court's mass death sentence.

Speaking on the eve of high-level meetings in Washington, Fahmy admitted that ties had experienced "turbulent times" since the 2011 revolution and the army's subsequent ouster of democratically-elected president Mohamed Morsi last year.

Al-Jazeera said Monday it has filed a claim against Egypt, demanding $150 million in damages suffered during a crackdown on the Qatar-based satellite network.

The pan-Arab television network said it lodged a formal "notification of dispute" with Egypt's military-installed interim government over damage since July 2013, when the army ousted Islamist president Mohammed Morsi.

The United States on Monday urged Egypt to reverse a court decision to sentence 682 alleged Muslim Brotherhood supporters, including the group's spiritual leader Mohamed Badie, to death.

"Today's verdict, like the one last month, defies even the most basic standards of international justice," the White House said.

Doctor Badawi was killed on August 14, but he was among 37 people whose death sentences were confirmed on Monday by an Egyptian court which sentenced another 683 to the gallows.

His case is not unique -- lawyers said two other defendants sentenced to death by the court in the central city of Minya for demonstrating in support of ousted Islamist president Mohammed Morsi were already dead on the day of the protest last year.

An Egyptian court sentenced 682 alleged Islamists and Muslim Brotherhood leader Mohamed Badie to death Monday, a lawyer and prosecutor said, after two brief sessions the defense partly boycotted.

The same court in the southern province of Minya also reversed 492 of 529 death sentences it passed in March, commuting most of those to life in prison.

Egypt's former army chief Abdel Fattah al-Sisi on Sunday urged an "unprecedented" turnout in a May presidential election he is expected to win almost 11 months after ousting the elected leader.

Sisi is expected to easily defeat his only rival, leftist Hamdeen Sabbahi, in the May 26-27 election, riding on a wave of support for overthrowing the freely elected but divisive Islamist president Mohammed Morsi on July 3.

An Egyptian court sentenced 42 supporters of deposed president Mohammed Morsi on Sunday to prison terms ranging from three to 15 years on violence-related charges, a judicial source said.

The verdict was delivered by Said Youssef Sabry, the same judge in the southern city of Minya who last month sentenced to death 529 alleged Islamists in a verdict that triggered international outrage.