A senior commander in Iran's Revolutionary Guard has warned that his forces will be on watch for possible unrest after next month's presidential election, calling the outcome "unpredictable" and sending the strongest message yet against any attempts to revive street protests, media reported on Sunday.

The entry of former president Akbar Hashemi Rafsanjani into the race has re-energized reformists and brought a backlash from hard-liners. The Guardian Council, a group controlled by the ruling clerics, vets all candidates and a final ballot list is expected on Tuesday.

Colonel Rasool Sanaeirad was quoted on Sunday as saying the "election is unpredictable", without elaborating.

He also warned that a "possible riot in Teheran could spread" to other regions, claiming chances for turmoil are heightened because Iran is for the first time holding both presidential and municipal balloting at the same time.

Heightened security

The remarks further suggest that more security controls could be imposed before the election.

Sanaeirad's comments were published in several newspapers, including the pro-reform Bahar daily.

On Friday, a member of the influential parliamentary committee of national security and foreign policy, Mohammad Saleh Jokar, said the government will block "enemies" using the Internet to "instigate people as we witnessed in 2009".

The pro-reform Aftab daily mocked the snail's pace of the Internet, calling it "escargot" and suggesting authorities would be better off to fully halt the net.

Presumed candidates on the ballot include Rafsanjani and rivals supported by the ruling clerics, such as top nuclear negotiator Saeed Jalili, Teheran Mayor Mohammad Bagher Qalibaf and former foreign minister Ali Akbar Velayati.

Ahmadinejad is not running in this election because Iran's constitution bars him from seeking a third term.

A major question is whether the Guardian Council will clear Ahmadinejad's choice, Mashaei. His chances are severely hampered by his association with the president, who has fallen out of favor with the ruling theocracy over his challenges to the authority of Supreme Leader Ayatollah Ali Khamenei.

Men executed

In a separate development, Iranian authorities executed two men on Sunday convicted of working for Israeli and US spy agencies, Iran's Fars News Agency reported.

Mohammad Heidari, accused of passing security-related information and secrets to Israeli Mossad agents in exchange for money, and Kourosh Ahmadi, accused of gathering information for the CIA in the United States, were hanged at dawn, it said.

Their death sentences were handed down by Teheran's Revolutionary Court and confirmed by the country's Supreme Court. The report did not say when the pair were arrested nor when their trial took place.