DUBAI, June 25 (Reuters) - Iranian authorities have rounded up at least 50 people suspected of links to militant groups in a Western province, a prosecutor said on Sunday, the latest in a wave of arrests following twin bomb and gun attacks in Tehran in early June. The arrests have been made days after Iranian Revolutionary Guards fired missiles from western Iran into eastern Syria, aimed at bases of the Islamic State which had claimed responsibility for the June 7 attacks in the capital Tehran that killed 18 people.

"Since the terrorist attacks in Tehran, more than 50 supporters and elements linked to terror groups have been arrested in Kermanshah province," provincial prosecutor Nemat Sadeqi told the state news agency IRNA.

"An appreciable number of suicide belts, electronic detonators, and weapons have been seized from the detainees," IRNA quoted Sadeqi as saying.

Iranian authorities have announced dozens of arrests following the Tehran attacks. On Saturday, state media said security forces arrested members of a group linked to Islamic State which had planned bombings and suicide attacks in Shi'ite Muslim religious centres.

The attacks by the Sunni Muslim militants at Iran's parliament and near the mausoleum of the Islamic Republic's founder exacerbated regional tensions.

Iran's Supreme Leader Ayatollah Ali Khamenei said afterwards the raids would increase hatred for Saudi Arabia, the region's main Sunni power, and the United States.

(Reporting by Dubai newsroom; editing by Sami Aboudi and Jane Merriman) ((dubai.newsroom@thomsonreuters.com))