The UN has slammed the Bahraini government over its decision to postpone the visit of special rapporteur on torture Juan Mendez.

Stressing that it was a "unilateral decision by the authorities", Mendez expressed his deep disappointment at the regime's decision.

"This is the second time that my visit has been postponed at very short notice. It is effectively a cancellation as no alternative dates were proposed nor is there a future roadmap to discuss," he said.

Mendez was originally to travel to the country in February 2012 but that visit was cancelled by Manama just a few weeks before his arrival.

Now his May visit has been called off "until further notice".

The announcement came just days after the release of a report on human rights in the Gulf kingdom by the US State Department which spoke of "serious human rights problems". They included "citizens' inability to change their government peacefully; arrest and detention of protesters on vague charges, in some cases leading to their torture in detention; and lack of due process in trials of political and human rights activists".

Ahead of the Formula 1 Grand Prix, authorities launched a crackdown on opposition activists, with local sources reporting an increased number of house raids and arbitrary detention of protesters.

Police fired teargas and clashed with students during a raid on Jabreya Secondary School for Boys in Manama in the runup to the race. Students had staged a protest demanding the release of recently arrested 17-year-old Hassan Humidan.

Mendez dismissed Bahrain's claims that he had put off his own visit.

"This was a unilateral decision by the authorities," he said. "It is not the first time the government has tried to avoid responsibility for the postponement of my visit, which was originally supposed to take place over a year ago."

He said that delaying a visit "could be perceived as if there is something to hide".

"At least it does not enhance transparency with regard to the situation in the country nor demonstrate a commitment to redress impunity regarding any violations. Rather, the authorities seem to view my visit as an obstacle rather than a positive factor to the reform process," he said.

Human Rights First slammed the Bahraini government's decision to cancel Mendez's visit to the country.

"The US government should publicly call for his immediate access to Bahrain," it said. "These delays only fuel the suspicion that the regime has a lot to hide."


Bahrain: Two Girls Arrested for 'Terror Plot' on Formula 1 Race