Iran's parliamentary speaker Ali Larijani warned Iran will not forgive Gulf Arab nations if they continue backing US "plots" against Tehran, local media reported on Sunday.
"We recommend to some of the countries in the region who were siding with (Iraq dictator) Saddam (Hussein) and now are siding with the US plots against the Iranian nation to give it up," he was quoted as saying.
"Iran will not forgive them again. There will be consequences in the region if new plots against our nation are carried out," Larijani said.
Larijani was referring to the generous financial aid and political support provided by Gulf Arab states, namely Kuwait and Saudi Arabia, to the Iraqi regime during the 1980-1988 war against Iran.
His comments come at a time when the United States and the European Union have imposed new sanctions on Iran's central bank and oil exports in January over its controversial nuclear programme.
Tehran has called on Saudi Arabia to reconsider a vow to make up for any shortfall in Iran's oil exports due to these new sanctions, saying Riyadh's pledge to intervene on the market was unfriendly.
Long-strained ties between Shiite-dominated Iran and Sunni-majority Saudi Arabia deteriorated after Saudi-led troops intervened in Sunni-ruled Bahrain in March help the government there crush Shiite-led pro-democracy protests.
The relations worsened late last year following US allegations that a foiled plot to assassinate the Saudi ambassador to Washington had been hatched in Tehran.
In addition, the Gulf Cooperation Council comprising of Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates, have called on Iran to "stop interfering in the internal affairs" of their nations.
The worsening ties continued after the six Gulf monarchies ordered their envoys home from Syria and expelled Damascus's ambassadors, joining mounting pressure on Syrian President Bashar al-Assad over the killings of civilians.
Tehran has been Damascus main regional ally since the 1979 Islamic revolution and has been supportive of Assad's regime in the 11 month uprising that has seen more than 6,000 people killed, according to human rights groups.