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 members of armed groups following a series of 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 details.

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.

Some of those facing execution were affiliated with Al-Qaeda, Okaz said. Others are from Awamiya, a largely Shia town in the oil-producing Eastern Province where the government has suppressed demonstrations for equal rights.

Diplomats in Riyadh say their governments have been assured Saudi Arabia will not execute Shia convicted after protests.

But Saudi courts have sentenced to death this year seven Shia men convicted of sedition for taking part in pro-democracy protests and attacks on police during demonstrations over discrimination from 2011 to 2013.

Two of those men, Ali Al-Nimr and Dawoud al-Marhoon were 17 at the time of the protests. Sentencing them to death to having bodies publicly displayed prompted an international outcry.

The only people executed so far for Al-Qaeda attacks in the kingdom in the last decade, which have killed hundreds, were two men from Chad earlier this year.

Awamiya residents responded to the news by closing off roads leading into the city with burning debris, local activists said.

The alleged Al-Qaeda fighters stand accused of attempts to overthrow the government and carry out attacks using small weapons, explosives and surface-to-air missiles, Okaz said.

One prisoner was accused of trying to buy nuclear material in Yemen worth $1.5 million for use inside Saudi Arabia.

The charges against the Awamiya residents include sedition, attacks on security officials and interference in neighboring Bahrain, which has also experienced unrest since 2011.

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.

Sympathizers of the Islamic State in Iraq and the Levant (ISIL) group have killed dozens in Saudi Arabia over the past 12 months with a string of mosque bombings and shootings aimed at members of the Shia Muslim minority as well as security officers and Western expatriates.

ISIL 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.

Wire services