MADRID (Reuters) - Spanish police announced the seizure of another five tonnes of cocaine on Friday, bringing to 15 tonnes the amount seized this week in an operation said to be the biggest drugs haul of its kind in Europe. The latest seizure took place during a raid at an abandoned building site near the northwestern town of Pontevedra, a National Police spokeswoman said. The first shipment seized, which included 10 tonnes of cocaine and 200 kg of heroin with an estimated street value of more than $1 billion, was mostly found on Sunday night aboard a ship off the Canary Islands. Officials proclaimed that haul a major blow against international drug trafficking rings which use Spain as one of the main entry points for smuggling cocaine from South America to Europe. Friday‘s seizure resulted from information police received while interrogating some of more than 50 suspects arrested earlier in the week. The seizure was believed to be the world‘s second largest, surpassed only by a 20-tonne cocaine haul in the United States in 1995. Previously the biggest cocaine seizure in Europe was 5.5 tonnes found by Italian police in 1994.