Over 70 countries are imposing entry restrictions or special quarantine measures on South Korean visitors amid a sharp surge in the number of patients infected with the novel coronavirus here, Seoul officials said.

On Saturday, a Vietnam-bound Korean flight carrying 40 passengers returned to the country after the Vietnamese government denied it permission to landing in the capital city of Hanoi.

The Vietnamese government notified Korean carriers on 8:30 a.m. Saturday to use Van Don International Airport in Quang Ninh Province, located three hours from Hanoi, rather than the city’s main airport, according to the Korean Embassy to Vietnam.

The flight, run by Asiana Airlines, arrived back at Incheon International Airport around two hours after departing for Hanoi at 10:30 a.m.

The airliner had to cancel the flight to Vietnam as the carrier had no history of using the suggested Vietnamese airport, according to a company official.

As of Saturday morning, South Korea reported 2,931 cases and 16 deaths. The tally is expected to climb during the weekend with tests still ongoing, especially in Daegu, the main center of the outbreak in Korea.

Despite the South Korean government’s request to refrain from entry bans, the number of foreign countries applying restrictions and strengthened quarantine measures on South Korean visitors is on the rise.

Nine more countries decided to increase regulations on travelers from South Korea overnight, bringing the total to 71 -- over one third of countries around the world. Among them, 33 countries put a full or partial entry ban into force, according to Seoul officials.

From March 1, Kyrgyzstan will prohibit entry to foreign nationals that have entered or passed through countries where the number of confirmed cases of COVID-19 has increased rapidly. Lebanon banned travelers from entering if they had visited locations hit by the virus outbreak, including South Korea.

Earlier, Saudi Arabia has put an entry ban on foreigners who visited Korea within 14 days of entering the country, although they can be admitted if they have a visa or residence card.

Meanwhile, South Korea’s Foreign Ministry urged travelers to exercise caution when travelling to Japan to reflect the latest developments of the outbreak of the coronavirus there.

Starting Saturday, the ministry issued a Level 1 travel advisory, or “blue” travel warning, which calls for caution, for those who stay or plan to travel any part of Japan.

“The announcement of the blue warning is taking into account that the number of infected people with COVID-19 in Japan is spreading recently, which is a concern about the exposure of Korean people to infection,” the ministry said in a statement.

Over 700 passengers and crew members on the Diamond Princess cruise, which has been in quarantine since it docked in Yokohama on Feb. 4. More than 200 other people within Japan have also tested positive for coronavirus.

By Park Han-na (hnpark@heraldcorp.com)