Trade unionist Reza Shahabi has been questioned while suffering from high blood pressure and other complaints, the campaign for his release said Monday.

Shahabi, a member of the Workers Syndicate of Tehran and Suburbs Bus Company (Sherkat-e Vahed), was arrested following a recent strike and protests by Tehran bus drivers. The campaign calling for his freedom said in a phone call from prison he had told his family he had high blood pressure, head and back ache, and that half his body was numb.

Shahabi was arrested May 12 as Tehran’s bus drivers began a strike over unpaid wages, creating chaos across the city with security forces in the streets and the government wary of possible protests over rising food prices.

Shahabi defended his meeting with two French citizens, trade union leader Cecile Kohler and her husband, after pictures were broadcast. Shahabi told his family during the phone call that there was nothing unusual in meeting trade union activists, although the pair, subsequently arrested, were in Iran as tourists.

In 2012 Shahabi was jailed for seven years on security charges - "gathering and colluding against state security" and "spreading propaganda against the system – two years after he was first imprisoned.

The bus workers syndicate said earlier in the month that a dozen drivers were detained after the strike.