Two brothers from Kosovo were convicted Thursday of running a massive drug smuggling ring that prosecutors said supplied Western Europe with up to half of its heroin.

Ragip and Kemal Shabani channeled 1.5 tons of heroin through Europe from the mid-1990s until 2003, when they were shut down, prosecutors said. They used a small town in Kosovo as their base with branches in Macedonia, Albania, Spain and the Czech Republic, according to the Federal Criminal Court.

The trial — considered one of Switzerland's largest-ever drug cases — was held under high security in the southern town of Bellinzona, with only some relatives and journalists allowed into the courtroom.

Judge Jean-Luc Bacher sentenced Ragip Shabani to 15 years in prison for breaking Swiss narcotics law, and ordered the 42-year-old to pay 300,000 francs ($261,400) in court costs.

Kemal Shabani, 28, was given only a two-year suspended sentence for participating in a criminal organization, and was charged 90,000 francs ($78,400) in court costs.