TEHRAN // The Iranian president Mahmoud Ahmadinejad accused the US president Barack Obama of behaving like his predecessor on Iran and called on him to apologise for what he called US interference following the Iranian elections. Mr Obama has ramped up his previously muted criticism, saying he was "appalled and outraged" by a crackdown on protests which followed Mr Ahmadinejad's disputed re-election. "Mr Obama made a mistake to say those things ... our question is why he fell into this trap and said things that previously Bush used to say," the semi-official Fars News Agency quoted Mr Ahmadinejad as saying. About 20 people have been killed in the demonstrations, but police and militia have flooded Tehran's streets since Saturday, quelling the majority of protests after the most widespread anti-government unrest since the 1979 Islamic revolution. The turmoil has dimmed prospects for Mr Obama's outreach to Iran over its nuclear programme, with Tehran blaming Britain and the United States for fomenting violence. "I hope you avoid interfering in Iran's affairs and express your regret in a way that the Iranian nation is informed of it," Mr Ahmadinejad said. Iran's reformist opposition leaders have vowed to press on with legal challenges to an election they say was rigged. The wife of opposition leader Mir Hossein Mousavi, who says he won the poll, said it was a "duty to continue legal protests to preserve Iranian rights". Mr Mousavi supporters said they would release thousands of balloons on Friday imprinted with the message "Neda you will always remain in our hearts" ? a reference to the young woman killed last week who has become an icon of the protests. Riot police swiftly dispersed a group of about 200 demonstrators with tear gas yesterday, but the protest was a far cry from marches last week that attracted tens of thousands. Protest cries were heard from Tehran rooftops again overnight, although they were much more short-lived than on previous evenings in the capital. The unrest has exposed unprecedented rifts within Iran's clerical establishment, with the supreme leader Ayatollah Ali Khamenei, who normally stays above the political fray, siding strongly with Mr Ahmadinejad. Ayatollah Khamenei has upheld the result of the June 12 presidential poll and has warned opposition leaders they would be responsible for any bloodshed. Iran's top legislative body, the Guardian Council, has also ruled out a call from Mr Mousavi to annul the election. *Reuters