DUBAI, Oct 1 (Reuters) - Some of the 50 people jailed in Bahrain on Sunday for security offences were also convicted of spying for Iran and had planned "vandalism and rioting" with the backing of the Islamic Republic, the Bahraini government said.
The 50 were sentenced to between five and 15 years in jail for links to February 14, an opposition movement seen by the authorities as a terrorist group working to overthrow the government, activists said on Sunday.
The Gulf Arab kingdom, base for the U.S. Navy's Fifth Fleet, has been in political turmoil since protests erupted in 2011 led by majority Shi'ite Muslims demanding full powers for parliament and an end to the Sunni monarchy's political domination.
Bahrain has accused Shi'ite Iran, seen as a regional troublemaker by several Gulf states, of fuelling the unrest, an accusation Tehran has denied.
In a statement, the government said the 50 were charged with founding and operating "a terrorist group with the goal of undermining the rules of the constitution and laws as well as preventing the institutions and public authorities from doing their work".
In addition, some of them had been convicted of spying for foreign states and their agents, or seeking to do so, with the aim of carrying out aggressive actions against the kingdom, it said, without specifying how many defendants this involved.
"It has been proved that they have spied for the Islamic Republic of Iran, and have been in touch with senior leadership and members of the Revolutionary Guards and supplied them with information related to the internal situation in the kingdom," the statement said.
"They have received directions from them related to training and preparation for carrying out acts of vandalism and rioting," it said, adding that evidence included video recordings of military training.
The Revolutionary Guards are an elite Iranian military force involved in internal security and defence, with a special unit that seeks to export Iran's revolutionary Islamist ideology.
The statement was issued to Reuters in response to a request for comment on Sunday's proceedings. The convictions were first reported by opposition activists, who said several human rights campaigners were among the defendants.
Sixteen of the defendants were sentenced to 15 years, four to 10 years and 30 to 5 years in prison, the statement said.
Lawyers for the defendants could not immediately be reached for comment.
There was no immediate word from the Iranian government. In February Iran's foreign ministry dismissed an earlier Bahraini allegation that the Revolutionary Guards had sought to set up armed opposition cells in Bahrain. (Reporting by William Maclean; Editing by Alistair Lyon)