Iran on Sunday accused US President George W. Bush of intervening in the Islamic Republic's internal affairs days after the American leader demanded that Tehran release four Iranian-Americans detained for alleged espionage. "Such expression is an obvious case of intervention in our domestic affairs," said Mohammad Ali Hosseini, spokesman of Iran's Foreign Ministry in a weekly news briefing. "They are Iranian nationals, and authorities are reviewing their case. They are in the investigations process." On Friday, Bush demanded that Iran "immediately and unconditionally" release the four Iranian-Americans and provide information about a former FBI agent missing in the country. The demand came as Iran in recent weeks has escalated accusations against the US, saying it had uncovered spy rings organized by the US and its Western allies.