Iranian negotiators have always been cautious about the risk of spying during talks with world powers about its nuclear program, a member of the country's negotiating team said Thursday.

The Swiss and Austrian authorities said Thursday their investigators had launched probes into alleged spying in hotels hosting the delicate talks on Iran's nuclear program.

The son of Iran's former president Akbar Rafsanjani will be jailed for 10 years after being convicted of financial and security crimes, judiciary spokesman Gholamhossein Mohseni-Ejeie said Thursday.

In March, Mehdi Hashemi was handed three jails sentences amounting to 15 years in separate cases involving national security as well as fraud and embezzlement.

Two Saudi Arabian airport workers have been jailed for four years each and will be lashed 1,000 times for sexually harassing two teenage Iranian boys, a report said on Wednesday.

Saudi news website Sabq said a criminal court in the Red Sea city of Jeddah issued the verdict.

A computer worm designed to gather foreign intelligence and widely linked to Israel was used to spy on negotiations with Iran on curtailing its nuclear program, security researchers said Wednesday.

A report by the Russian-based security firm Kaspersky Lab said it discovered the malware dubbed Duqu lurking in its own internal networks and linked the effort to intelligence gathering on the 2014-15 talks with Tehran.

Iran on Wednesday insisted it has not deployed troops in Syria to strengthen regime forces, denying reports that thousands of foreign fighters have been flown in to help defend Damascus.

Reports on "the military presence of countries friendly to Syria" are "unfounded", foreign ministry spokeswoman Marzieh Afkham said at her weekly press briefing.

Three suspected al-Qaida members were killed in an apparent U.S. drone strike in Yemen's jihadist-held southeastern port city of Mukalla, a local official told Agence France Presse on Wednesday.

The drone "fired four missiles at three al-Qaida militants" near Mukalla port late Tuesday, killing them on the spot, said the official.

Iran has told the U.N. Security Council that Saudi-led air strikes have twice hit close to its embassy in Yemen and warned of "serious consequences" if more such bombings occur.

Iran's ambassador to the United Nations Gholamali Khoshroo said in a letter released Tuesday that the embassy in Sanaa suffered severe damage during air strikes on May 25 and that this followed a similar attack on April 20.

Saudi Arabia has summoned Iran's ambassador over a mass poisoning which killed four children and left 28 other Saudi pilgrims sick, official media said on Tuesday.

Riyadh called in the envoy "to express its serious concern over the incident, hoping the Iranian authorities quickly carry out investigation procedures to uncover the circumstances", said Osama Nugali, the foreign ministry's information division chief, quoted by the Saudi Press Agency.

The U.N. Security Council on Tuesday voted to keep intact a panel of experts monitoring sanctions on Iran as negotiations on a nuclear deal head into the final stretch.

The 15-member council unanimously adopted a resolution renewing the mandate of the panel until July 2016.

CIA chief John Brennan made a "secret" visit to Israel last week to discuss an emerging nuclear deal between Iran and world powers, Israel's Haaretz newspaper reported on Tuesday.

It came as a June 30 deadline looms for a deal that would row back Iran's nuclear program in return for relief from sanctions, which Israel has long opposed, causing friction with the White House.