Prominent Bahraini activist Nabil Rajab appealed on Wednesday for the world to impose sanctions on his country, which he said had slipped into "dictatorship".
Rajab, who was released last month after spending two years in jail for taking part in "unauthorised demonstrations", said the country had "turned much worse" during his absence.
The head of Bahrain's Centre for Human Rights was arrested after taking part in a month of Shiite-led protests in 2011 demanding political reforms.
During his time in prison, "a lot of laws were created, a lot of measures were taken which have changed the system into dictatorship," he told reporters in Geneva.
Rajab, who was holding his first media conference since his release on May 24, claimed that between 3,000 and 4,000 political prisoners were languishing in jail in Bahrain, a country of some 700,000 people.
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"I came to urge all civilised nations, civilised governments to take measures against my country," he said, calling on the international community to disregard commercial interests in Bahrain and impose sanctions.
European countries especially "can do much more to help the situation inside," he said, insisting that "democratic countries like the UK, France and EU countries should take very tough positions and stand firm".
Bahrain's opposition has campaigned for the establishment of a genuine constitutional monarchy in the country.
It took part in two rounds of national dialogue with the government, before quitting the negotiations complaining that the authorities were not prepared to make enough concessions.
Rajab said on Wednesday he was planning to take his message on to Paris and the Scandinavian countries in coming days, before heading home to Bahrain, despite the risk of being arrested again.
Strategically located just across the Gulf from Iran, Bahrain is home to the US Navy's Fifth Fleet and is a major offshore financial and services centre for its Arab neighbours in the oil-rich Gulf.