(ANSA-AFP) - TIVAT, JUN 4 - Montenegro police said they had turned back a plane filled with suspected Serbian govenment supporters on Wednesday, as authorities promised to crack down on "destabilisation" ahead of an EU-Western Balkans summit. Police in the port town of Tivat, which is to host a meeting between European and Western Balkan leaders on Friday, said they had refused entry to around 90 men who "would represent a risk to internal and national security" after they landed on a flight from Belgrade. Police had found a maritime radio device, a banner bearing the slogan of Serbia's ruling party and evidence that several of the men were known to attend pro-government rallies and events in Belgrade. "These are persons who attended numerous public gatherings of high security risk," Montenegro's police directorate and national security agency said in a joint statement. According to the statement, some of the men had violent criminal pasts. (ANSA-AFP).