KUALA LUMPUR - Malaysian authorities have arrested 13 people believed to be part of cells linked to Islamic State (IS), the inspector-general of police said on Thursday.The suspects were caught in an anti-terror sting launched on Wednesday, the latest arrests in an ongoing operation to clamp down on the spread of militancy in the Muslim-majority country.The Malaysian police also confiscated IS-linked documents during the raid, inspector general Khalid Abu Bakar said in a Twitter posting.The announcement of the arrests was made after Khalid said in an interview, published on Thursday by local daily The Star, that police will set up a counter-terrorism unit in every state in the country.