"We are certain that Gulf countries will not back the United States in waging an attack on Iran," Rafsanjani said on the second day of a visit to Kuwait aimed at allaying fears in the region over Iran's nuclear activities.

Rafsanjani, who heads Iran's powerful Expediency Council, was in parliament to meet with Kuwiati deputies after holding talks with the emir Sheikh Sabah al-Ahmad al-Sabah.

"The talk about a US attack on Iran is nonsense and we are sure the Americans would not want create problems for themselves," he said.

Rafsanjani's visit follows Iran's announcement last week that it had successfully enriched uranium to the level needed to make reactor fuel, triggering global concern about its nuclear ambitions.

Uranium enrichment can be extended to make weapons, and the UN Security Council has given Iran's hardline leadership until April 28 to freeze the sensitive fuel cycle work.