An Iranian nicknamed "The Blogfather" and credited with starting the country's blogging revolution has been arrested and accused of spying for Israel.

Hossein Derakhshan, who holds joint Iranian-Canadian citizenship, returned to Iran three weeks ago, having left for Canada in 2000 with his wife.

Using his Canadian passport, the 33-year-old from Tehran attracted widespread publicity when he visited Israel in 2006 "to be a bridge between the Iranian and Israeli governments". He also criticised Iranian president Mahmoud Ahmedinejad in an article for the New York Times.

However, observers had noted that since his return to Tehran his blogging had begun defending Iran's right to own defensive nuclear weapons and showing some support for President Ahmedinejad's anti-American stance. According to national newspaper reports on Wednesday, his change in attitude towards the regime had turned away many who had followed his blogging previously.

Meanwhile, Iran was reported on Monday to have executed a man accused of spying for Israel. The semi-official Fars agency put out a story saying that 45-year-old Ali Ashtari had been hanged. It reported that he had been arrested two years ago and confessed to spying for Israel using security and telecommunications equipment.