Saudi Arabia executed 81 men over the past 24 hours, including seven Yemenis and one Syrian national, on charges including terrorism and holding "deviant beliefs", state news agency SPA said on Saturday.

The number dwarfed the 67 executions reported in the kingdom in all of 2021 and the 27 in 2020.

"These individuals ... were convicted of various crimes including murdering innocent men, women and children," SPA said, citing a statement from the interior ministry.

"Crimes committed by these individuals also include pledging allegiance to foreign terrorist organisations, such as ISIS (Islamic State), al-Qaeda and the Houthis," it added.

Some travelled to conflict zones to join "terrorist organisations", SPA said.

The men included 37 Saudi nationals who were found guilty in a single case for attempting to assassinate security officers and targeting police stations and convoys, the report added.

Saudi Arabia's human rights records have been under an increasing scrutiny from rights groups and Western allies since the killing of Saudi journalist Jamal Khashoggi in 2018.

It has faces strong criticism of its restrictive laws on political and religious expression, and the implementation of the death penalty, including for defendants arrested when they were minors.

Saudi Arabia denies accusations of human rights abuses and says it protects its national security according to its laws.

SPA said the accused were provided with the right to an attorney and were guaranteed their full rights under Saudi law during the judicial process.