Danish student 'arrested in Iran'

A Danish journalism student has been arrested in Iran after covering anti-government protests, unions say.

The Danish Union of Journalists named the student as Niels Krogsgaard, 31.

Wednesday's Tehran protests coincided with an official rally to mark 30 years since the storming of the US embassy during the 1979 Islamic revolution.

A Canadian, a Japanese and an Iranian journalist are also being held for covering the protests without permits, the semi-official Fars agency reports.

Iran has tightened reporting rules since protests flared in the days following a disputed presidential election in June.

Opposition supporters say the elections were rigged to ensure the re-election of President Mahmoud Ahmadinejad.

At least 30 protesters have been killed in clashes since the elections. Thousands have been arrested, and some 200 opposition activists remain behind bars. Three have been sentenced to death.

Batons and tear gas

Mr Krogsgaard was in Tehran working on an academic paper about Iranian politics, said the Danish Union of Journalists.

He was "apparently arrested in connection with a demonstration on Wednesday", the union was quoted as saying by the Associated Press news agency.

Security forces had used batons and tear gas to disperse protesters and there were unconfirmed reports the authorities had also opened fire.

Video footage and photos showed what appeared to be large crowds of opposition supporters being chased by security forces in riot gear.

Many of the opposition demonstrators wore green scarves or bands, which have been used in repeated protests since Iran's disputed presidential elections in June.

Thousands were present at the anti-American rally, about 1.5km (1 mile) from where opposition supporters gathered in Haft-e Tir square.

In November 1979, 52 US diplomats were taken hostage at the embassy and held for 444 days by Islamist students in support of the Iranian revolution.