Thailand police are showing they’re serious about combatting illegal World Cup betting, having made over 3,000 arrests in the 2018 tournament’s first four days.

On Monday, deputy national police chief Chalermkiat Srivorakhan announced that about 250 of the 3k gamblers and illegal bookmakers nabbed so far were caught in the Bangkok region and its adjacent provinces.

The deputy chief noted that gambling activity was higher than recorded during the 2014 tournament “because people have easy access to football gambling websites via mobile phones.” The top cop said police had identified thousands of online football betting sites promoting their wares to Thai bettors, but only around 100 of these sites were hosted in Thailand.

Metropolitan Police Bureau deputy commissioner Phanurat Lakboon told the Bangkok Post that the police had limited options when trying to eradicate online betting, much of which was conducted via licensed sites in Cambodia. “We can’t tell Cambodia to close down its online gambling websites because gambling is legal there.”