LONDON: PUNITIVE international sanctions imposed on Iran have strengthened the government of Mahmoud Ahmadinejad and helped its post-election crackdown on the opposition movement, a leading reformist politician and former presidential candidate says.

More than a year after widespread unrest erupted after Mr Ahmadinejad's disputed re-election as President last June, Mehdi Karroubi blamed the US and Britain for adopting counterproductive policies to combat Iran's suspect nuclear program, describing sanctions as a gift to the regime.

Isolated ... the regime is cracking down on opposition.

''These sanctions have given an excuse to the Iranian government to suppress the opposition by blaming them for the unstable situation of the country,'' Mr Karroubi said in emailed responses to questions.

Mr Karroubi, 73, a former speaker of parliament under the reformist president Mohammad Khatami, and a candidate in last year's election, said isolating Iran would not bring democracy.