The deputy head of Iran's powerful Revolutionary Guards (IRGC) told Saudi Arabia on Thursday it would "collapse" in coming years if it kept pursuing what he called its sectarian policies in the region.
Saudi Arabia, Bahrain, Sudan and Djibouti broke off ties with Iran this week, the United Arab Emirates downgraded its relations and Kuwait and Qatar recalled their ambassadors after the Saudi embassy in Tehran was stormed by protesters.
Tensions between Shi'ite Muslim power Iran and the conservative Sunni kingdom have spiralled since Saudi Arabia on Saturday executed cleric Sheikh Nimr al-Nimr, an opponent of the ruling dynasty who demanded greater rights for Saudi Arabia's marginalised Shi'ite minority.
"The policies of the Saudi regime will have a domino effect and they will be buried under the avalanche they have created," the IRGC's second-in-command, Brigadier General Hossein Salami, was quoted as saying by the Fars news agency.
"If the Saudis do not correct their path, their regime will collapse in coming years."
Salami compared Saudi policies with those of Saddam Hussein, the Iraqi president overthrown by U.S. forces in 2003.
"The path the Saudi regime is taking is like the one Saddam took in the 1980s and 90s. He started a war with Iran, executed prominent clerics and top officials, suppressed dissidents and ended up having that miserable fate."
Saddam, a Sunni, was hanged in 2006 after being convicted of crimes against humanity for the killing of 148 Shi'ite villagers after a failed assassination bid in 1982.
Salami called Riyadh's decision to cut ties with Iran "irrational and hateful" and said the violence in Iraq and Syria were "the direct results of Saudi's sectarian policies in the region".
Iran has accused Saudi Arabia of using the attack on the embassy as an excuse to sever ties and increase sectarian tensions.
The IRGC promised "harsh revenge" against the Saudi royal dynasty for Nimr's death, saying it would "cost Saudi Arabia dearly".