Bahrain has suspended all activities of the country’s main opposition group, according to a statement from the Justice Ministry.

The statement added that the Shia group, called Al-Wefaq National Islamic Society, which has been leading pro-democracy protests since 2011, has been closed and all its assets frozen.

Al-Wefaq was served court papers on 14 June that claimed it had damaged Bahrain’s national security, a lawyer working for the organisation was quoted as saying by the Associated Press news agency.

The group’s leader, Ali Sheikh Salman, who was arrested in late 2014, was recently handed an extended sentence of up to nine years for “inciting hatred against the regime and threatening national security”, according to a local court.

Bahrain’s Shia majority often say they do not receive the same benefits as Sunni citizens, with many claiming they have limited opportunities.

In 2011, a wave of pro-democracy protests took place across the country before the authorities brought in troops from neighbouring Sunni-led Gulf states to control dissent. At the time it was reported that 35 people were killed.