Human rights group have warned of possible violent crackdown in Bahrain and condemned the use of arrest and torture ahead of mass anti-government protests organised by the country's Tamarod (rebel) group for Wednesday (14 August).

Amnesty International warned Bahraini authorities against a crackdown on major rallies calling for an end to repression. The NGO also called for "genuine political reforms".

"The people of Bahrain have the right to express their views freely and to protest peacefully without the threat of violence," said Philip Luther, Middle East and North Africa director at Amnesty.

"For years the authorities in Bahrain have shamelessly sought to stifle freedom of expression, taking increasingly drastic steps to stamp out dissent with complete disregard for international law."

August 14 marks the day when Britain completed its withdrawal from the tiny gulf kingdom, in 1971, and Bahrain gained independence. Tamarod is a loose opposition group of activists who push for "free and democratic Bahrain" through mass demonstrations.

A number of security measures have been put in place, including the erection of barbed wire fences and other barriers around villages to prevent demonstrations. Maryam al-Khawaja, acting president of the Bahrain Centre for Human Rights (BCHR), said: "They're caging entire villages with barbed wire."

Prime Minister Sheikh Khalifa bin Salman al-Khalifa said his government would "forcefully confront" protests, according to Bahrain News Agency.

"The government will forcefully confront the suspicious calls to violate law and order and those who stand behind them through decisive measures," he said.

"It will punish [those] who stand behind them in line with the recommendations of the Bahrain national council [parliament], which represents the will of the people of Bahrain."

A series of decrees approved by the king of Bahrain have been introduced to harden the 2006 counter-terrorism law.

The measures include a ban on all public gatherings and demonstrations in the capital Manama. Parents of anyone under 16 years of age who takes part in a demonstration will receive a written warning from the Ministry of Interior and could face longer prison terms, fines or be stripped of Bahraini nationality.

"These draconian new measures are disgraceful. National security must not be used as an excuse to sanction the repression of peaceful protests," said Luther.

Khalifa accused the protesters of seeking to spread chaos and topple the government.

Reporters Without Borders said it was concerned by a new wave of "abusive treatment of journalists" ahead of the Tamarod rally.

"The authorities plan to impose a news blackout on the 14 August demonstration by jailing netizens and preventing journalists and human rights defenders from visiting Bahrain," it claimed.

"They have had no hesitation about arbitrarily arresting news providers and denying them access to lawyers while failing to bring formal charges against them. We call for their immediate and unconditional release."

Two bloggers, two photographers and a cameraman have been arrested in Bahrain since the end of July. Among them are blogger Mohamed Hassan and photographer Hussain Hubail. Hassan said that he was tortured in detention.

Other journalists have been blocked from entering the country, including Hyder Abbasi of Al Jazeera English.