Thailand said Monday that the country has found its first case of Omicron variant of COVID-19 after confirming that a U.S. visitor arriving from Spain tested positive.

The 35-year-old traveller, flying from Spain by transiting through Dubai, entered with a negative RT-PCR test, but the on-arrival test returned a positive result on Dec. 1 and further test results confirmed the presence of the new Omicron strain, the Ministry of Public Health announced Monday.

According to the ministry, the passenger, currently under treatment at a hospital in Bangkok, was asymptomatic, and there has been no high-risk contacts as the patient has taken strict precautions during his trip.

On Monday, Thailand reported 4,000 new COVID-19 cases and 22 more deaths during the last 24 hours, raising the total number of infections to more than 2.14 million while that of cumulative fatalities to 20,966, according to the ministry.