RIYADH, Saudi Arabia — Saudi Arabia plans to execute more than 50 people convicted of terrorism, two Saudi newspapers reported this week, in what appears to be a warning to would-be jihadis at a time of militant attacks on the kingdom.

Fifty-five people were awaiting execution for "terrorist crimes" that killed more than 100 civilians and 71 security personnel, the newspaper Okaz reported on Thursday, without specifying when the executions would occur.

On Monday, the semi-official newspaper al-Riyadh reported that 52 people would be put to death soon, but it later pulled the story from its website without explanation.

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Some of those facing execution were affiliated with al Qaeda and stand accused of attempts to overthrow the government and carry out attacks using small weapons, explosives and surface-to-air missiles, Okaz reported.

Saudi Arabia has already executed over 150 people this year, mostly by public beheading, the most in 20 years, rights group Amnesty International said this month.

The Saudi monarchy has in recent years sentenced to death dozens of people convicted of taking part in al Qaeda attacks in Saudi Arabia from 2003-2006 and again in 2009.

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ISIS sympathizers have killed dozens in Saudi Arabia over the past 12 months with a string of mosque bombings and shootings aimed at members of the Shiite Muslim minority as well as security officers and Western expatriates.

The Syria and Iraq-based militant group has called on its followers in Saudi Arabia to stay home and conduct attacks there instead of traveling to join the caliphate it declared in 2014.

The last time Saudi Arabia carried out mass executions for security offences was after a group of Islamist militants seized Mecca's Grand Mosque in 1979.