"The number of confiscated devices was 12,000... in recent months, although the actual figure in my opinion is much higher," Saud al-Qahtani, an adviser to powerful Crown Prince Mohammed bin Salman, told AFP.
"Saudi Arabia respects the issue of protecting intellectual rights and abides by international conventions in this regard," he added.
His statement comes as sports broadcaster beIN -- which has exclusive Middle East rights to televise this year's World Cup -- alleges it is a victim of a major pirating operation based in Saudi Arabia.
BeIN has said that since last October, a vast and sophisticated Saudi bootlegging network known as "beoutQ" -- using a signal from Riyadh-based satellite provider Arabsat -- has been illegally transmitting its broadcasts.
Illegal transmissions from beoutQ had appeared in Morocco, Jordan and Syria, and it was likely they would reach Asia and southern Europe, according to beIN.
The Qatari broadcaster has urged football's governing body FIFA to take legal action against the pirate broadcasters.
"Saudi Arabia takes this issue seriously and continues to organise inspection campaigns in coordination with all relevant parties," Qahtani said.
The piracy claim comes at a politically sensitive time in the Gulf, with Qatar boycotted by Saudi Arabia and its allies, in a highly fractious year-long diplomatic and economic dispute.
Qatar has been isolated since June 5, 2017, accused by the Saudi-led bloc of supporting terrorism and being too close to Riyadh's archrival, Iran.
Qatar denies the charges and says the dispute is an attack on its sovereignty.
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