The group was planning to hold a protest outside the house, calling for the release of Mansur Osanlu and another jailed union activist, Mahmud Salehi.
The gathering was part of what organizers hoped would be a worldwide day of protests to free the two men. The International Transport Workers Federation (ITWF) said its union affiliates would demonstrate in front of Iranian embassies in their countries, request meetings with Iranian diplomats, and present letters of protest.
A Radio Farda correspondent in Australia reported today that a group of Iranians had gathered in front of Iran's embassy in Canberra. Similar rallies were reported in Sweden and Germany.
The head of the Tehran bus drivers' union, Osanlu was detained on July 10. Salehi, a bakers union activist, was detained on April 9 in Iran's western Kurdistan Province.
In Tehran today, Osanlu's wife, Parvaneh, tells Radio Farda that security forces surrounded the house, preventing anyone from entering.
"There are a lot of security personnel in front of our door," she says. "We feel insecure, of course. My children are worried and upset; it's a very abnormal situation. We're innocent here, we have nothing, we are under pressure for nothing."
Radio Farda reports that five members of Tehran's bus drivers union were detained before entering the house.
The union was planning to hold a rally outside the house today.
Salehi's wife expresses cautious optimism about today's global campaign.
"I'm optimistic regarding this campaign, [but] we can't be 100-percent optimistic that Iranian officials will retreat from the sentences and arrests [of workers and union activists]," Parvaneh Osanlu says.
The Brussels-based ITWF says it is "extremely worried" about the health of both Osanlu and Salehi, who have been deprived of legal representation or medical care.
Mansur Osanlu in early 2007