Bahrain has detained a former member of parliament on charges of financing militants, state news agency BNA said.

The agency did not name the man but quoted the director of criminal investigations as saying he was held on August 18 after returning from a trip to collect funds in Iran.

The director of criminal investigation said the detainee had collected donations from various sources, including participants in rallies, to give to suspects being sought by the authorities as well as "a terrorist group" knowing about its activities.

The charges he was facing amounted to "financial terrorism", the director was quoted as saying. "He said the name of the arrestee was mentioned in a number of terrorist cases, including the Sitra terrorist blast on July 28 that killed two policemen," BNA said.