Thailand confirmed a fourth persons case of the coronavirus on Sunday increasing the number of people to have tested positive after it opened its borders to people returning home from Iran near the epicenter of the outbreak in other East Asian countries.

The southern province of Pattani announced a ban on international travel between the two countries after officials lifted a nationwide quarantine on people returning from Iran.

The country earlier this month sealed off two provinces and introduced a seven-day self-quarantine for people arriving from the two countries.

But after easing restrictions for several weeks Beijing and Bangkok reported cases in some of their largest communities including two cases of fever in Bangkok as well as two in the coastal town of Prahrit.

The World Health Organization has placed Thailand in a high-risk group saying the positive test rate was could rise to 20 per 100000 after taking into account travel patterns and social distancing measures imposed by citizens.

Health authorities said on Sunday they had tested the new cases with the first positive being a woman in Pattani aged 31 according to the health ministry website. She was having her positive test tested again while her 12th case reported elsewhere was a man aged 24 who had joined the virus.

Thailand came under pressure to reopen its borders in June as the number of infections in the country spiked to 189 the highest since March last year when 28 cases were recorded.

Thailand announced the first confirmed case of the coronavirus in Cambodias owner Nirom Singh whose company runs a hotel in Joc 40 km (25 miles) away from Pattani.

Heath Minister Kusik Rustamirawong told a news briefing that all foreigners who came from China to Thailand since Jan. 23 in order to be free of the virus had been quarantined.

All Thai university students and visiting foreign nationals are also required to self-isolate for 14 days. The government has accused some people of spreading false information seeking to destabilise the authorities.