Mahmoud Ahmadi-Nejad said his declared re-election as president of Iran on Sunday was a “blow to the oppressive system ruling the world” after a weekend in which thousands of protesters clashed with police and his rivals called for a rerun.

Western leaders expressed dismay at the disputed results that awarded a landslide victory to the firebrand incumbent, with Joe Biden, the US vice-president, saying there was “real doubt” about them. Avigdor Lieberman, Israel’s hardline foreign minister, called for co-ordinated action against Mr Ahmadi-Nejad.