Pro-Palestinian protesters demand that the institution condemn Israel's actions, in a protest that echoed similar demonstrations on US campuses
Europol said the suspected ringleader, a 48-year-old Latvian, had been arrested in Spain. The other suspects were detained by police in Poland, Lithuania, Spain and Britain.
The agency described the operation as the largest of its kind, with 40 houses searched on May 15 and 16, resulting in the seizure of 8 million euros ($8.92 million) in cash, diamonds, gold bars, jewellery and luxury cars.