Saudi Arabia warned Sunday of "suitable measures" if providers of Internet messenger applications such as WhatsApp fail to comply with its rules, days after the industry said authorities wanted to control such traffic.

"Some telecom applications over the Internet protocol currently do not meet the regulatory conditions" in the kingdom, said the Communications and Information Technology Commission in a statement carried by the official SPA state news agency.

A mortar attack that killed 15 students at Damascus University marks a rebel escalation in the Syrian capital ordered by foreign governments, Information Minister Omran al-Zohbi said on Friday.

"The terrorists' mortar attacks on residential areas, schools, universities and hospitals is the result of foreign orders to stage a full-scale escalation," Zohbi told state news agency SANA.

Head of al-Mustaqbal parliamentary bloc ex-PM Fouad Saniora will head a delegation to Saudi Arabia on Saturday for talks with former PM Saad Hariri to brief him on the ongoing consultations among the parties affiliated in March 14 alliance.

According to al-Joumhouria newspaper published on Friday, Saniora and the accompanying delegation will discuss with Hariri, who is currently in Riyadh, the formation of the cabinet, the new electoral law and the critical situation the country is passing through.

Iran's foreign ministry has strongly protested against a Saudi accusation that it was directly linked to an alleged spy cell busted last week in the kingdom, Iranian media reported on Wednesday.

Saudi Arabia's interior ministry said on Tuesday that the cell it dismantled last week had "direct links" to Iran's intelligence services.

Saudi authorities on Wednesday beheaded a Yemeni man and then crucified his body after he was convicted of murdering a Pakistani national, the kingdom's interior ministry announced.

"The Yemeni citizen Mohammed Rashad Khairi Hussein killed a Pakistani, Pashteh Sayed Khan, after he committed sodomy with him," said a statement carried by state news agency SPA.

An alleged spy cell dismantled last week in Saudi Arabia had "direct links" to Iran's intelligence services, the kingdom's interior ministry said on Tuesday.

"Preliminary investigations and physical evidence that has been collected as well as the defendants' statements on this case have all revealed direct links between this cell and Iranian intelligence services," a ministry spokesman said in a statement carried by the official SPA news agency.

Internet messenger applications such as Skype, Viber and WhatsApp face being banned in Saudi Arabia if operators fail to allow authorities in the kingdom to censor them, industry sources said on Monday.

Local telecommunication providers have been told to ask the operators of the services to furnish means of control, an official at the kingdom's Communications and Information Technology Commission said, requesting anonymity.

The Saudi Interior Ministry warned on Monday that Saudis fighting in Syria will be arrested when they return home.

Maj. Gen. Mansour al-Turki, the ministry's spokesman, said: "Involvement in the Syrian crisis is against Saudi laws."

Iran has denied any link to a spy cell dismantled in Saudi Arabia, after Riyadh said an Iranian is among 18 suspects arrested on charges of espionage for a foreign country, media reported on Sunday.

"This is without any foundation. It is a scenario that is being repeated... for domestic consumption," foreign ministry spokesman Ramin Mehmanparast was quoted as saying.

Interior Minister Marwan Charbel revealed on Thursday that Saudi authorities are carrying out “secret” interrogations with a Lebanese businessman, who is allegedly suspected of espionage for a foreign country.

“We haven't received yet any information about the suspect,” Charbel said in comments published in the pan-Arab daily pan-Arab daily Asharq al-Awsat.