A Saudi diplomat and his bodyguard were killed in broad daylight when their car was raked with gunfire by unidentified assailants in the Yemeni capital on Wednesday, a diplomatic source said.

"Gunmen dressed in the central security forces' uniforms opened fire heavily at the car of the Saudi diplomat in Sanaa, causing it to flip over, killing him and his bodyguard," the source told AFP on condition of anonymity.

Saudi Arabia's grand mufti has slammed popular protests across the region as anti-Islamic, saying they only serve to spread chaos, local media reported on Wednesday.

"These protests are not linked in any way to Islam, which promotes dialogue," Sheikh Abdul Aziz bin Abdullah al-Sheikh was quoted as saying by Al-Eqtisadiah daily.

Saudi authorities on Tuesday beheaded two nationals for murder, including one who stabbed his wife to death and burned her corpse, the interior ministry said.

Ali Mohammed Mahrazi was convicted of stabbing his wife Hunayna Khabrani repeatedly before he "poured kerosene on her body and set it on fire until it was charred," the ministry said in a statement carried by SPA state news agency.

Saudi Arabia's crown prince on Monday assured cabinet members over the health of King Abdullah, 89, who underwent back surgery on November 18 and has since remained in hospital, state news agency SPA reported.

It said Crown Prince Salman bin Abdul Aziz chaired a cabinet meeting and "assured (ministers) over the health" of the ailing king, of whom no photograph has been released since his hospitalization.

Saudi Arabia on Monday beheaded three men convicted of separate murders across the kingdom, the interior ministry announced.

Mubarak al-Harithi and Obaidallah al-Harithi, whose nationality was not given, were executed in Mecca province for having stabbed and shot dead a victim named as Ayedh al-Harithi, it said in a statement carried by official news agency SPA.

A Palestinian was beheaded in Saudi Arabia on Monday after being convicted of forming a gang to carry out robberies in the kingdom, the interior ministry said.

Mohammed al-Khalili "formed a gang with others that carries out thefts, burglaries, and robbery against homes," said the statement carried by the official SPA news agency.

King Abdullah of Saudi Arabia, 89, has "successfully" undergone a new operation on his back, the royal cabinet announced Sunday.

The operation, to correct "a ligamentary slackening in the upper back" of the monarch, ended at dawn on Sunday, said a statement quoted by the official SPA news agency.

Billionaire Saudi Prince Walid bin Talal's Kingdom Holding investment group said Saturday it has purchased the luxury hotel Four Seasons Toronto, Canada for $200 million.

"The transaction was funded by a $130 million mortgage loan while $70 million came from (the company's) own resources," Hazem al-Dosari, a Kingdom Holding Company spokesman, told AFP.

Saudi Arabia's 89-year-old King Abdullah will undergo back surgery in Riyadh at noon on Saturday, state news agency SPA reported.

The monarch "will undergo a surgical operation to treat the looseness in the conjoining cord in the upper back at noon on Saturday in the King Abdulaziz Medical City for the National Guard," said SPA.

Saudi Arabia urged its citizens to stay away from public gatherings and universities in Jordan, where riots over fuel price hikes have left one person dead and 71 wounded, state news agency SPA reported.

The kingdom's embassy in Amman "warned Saudi employees and students in Jordan from going to public squares or approaching sites of gatherings and demonstrations," SPA said late on Thursday.