The couple were arrested on Sunday evening on a plane that was about to take off from Amsterdam Airport Schiphol, according to Dutch police.
Officers did not disclose the names and nationalities of those detained, but city newspaper Het Parool reported that it was a Spaniard and a Portuguese woman attempting to fly to Spain.
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The couple were staying at a quarantine hotel in the Kennmerland area, where travelers from South Africa who have tested positive for COVID-19 are self-isolating.
Of more than 600 passengers on two flights from Cape Town and Johannesburg, 61 have tested positive for COVID-19 – and 13 of them were infected with the Omicron variant.
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It is not known if the couple were among these travelers.
They have been turned over to health authorities and could face prosecution for violating Dutch quarantine rules, De Telegraaf reported.
Their arrest was made “without violence”, adds the newspaper.
Private hotel security guards keep guests isolated, while police outside ensure that no one enters the premises if they don’t need to be there.