TEHRAN • Iranian security forces arrested five members of Tehran's bus drivers' union after they visited the home of their imprisoned chief, the men's lawyer said yesterday.

Tehran and suburbs bus drivers' union chief Mansour Ossalou, who has pushed for stronger trade unions in Iran, has been detained in Tehran's Evin prison since July after being convicted of acting against national security.

"Ebrahim Madadi, Yagoub Salimi, Davoud Razavi and Ghojari and Homayoun Jaberi went to Mansour Ossalou's house to meet his family, where they were arrested," said lawyer Parviz Khorshid, quoted by the Isna news agency.

"These arrests are illegal as these people simply wanted to meet the family of Mansour Ossalou. I hope that they will be released, even today," he added, without saying when the five were arrested.

Ossalou has been sentenced to four years in prison for acting against national security and to an additional year for disseminating propaganda against Iran's Islamic system.

Tehran's Deputy Prosecutor for Security Issues, Hassan Hadad, said he had been arrested "while distributing pamphlets against the system" and denied Ossalou's detention was linked to his union activities.

"His case has nothing to do with labour issues," Hadad told the state-run Irna news agency in an interview published yesterday.

Hadad said he had talked personally to Hadad's mother, his wife and the prisoner himself.

"We all reached an agreement but he did not fulfill it," he said, without giving further details.

Ossalou had previously been jailed between December 2005 and August 2006.

Rights group Amnesty International, the Brussels-based International Trade Union Confederation (ITUC) and the International Transport Workers' Federation held protests in European capitals on Thursday calling for his release.

They also called for the release of Mahmoud Salehi, a prominent trade unionist and former head of the bakers' union in Iran's Kordestan province, who was rearrested in April after serving previous jail terms.