The U.S. says that citizens from 35 countries could be barred from boarding U.S.-bound flights starting in March if they don't register online before flying.

USA Today is reporting that Washington hopes the new registration will flag visitors with criminal records or immigration problems before they enter the U.S.

The registration requirement affects 35 countries --- including the U.K., Japan, Germany and South Korea --- whose citizens can enter the U.S. without a visa. Korea gained the visa waiver status in late 2008.

Starting March 21st, U.S. Customs said it may start fining airlines up to 33-hundred dollars for each passenger who has failed to register and is allowed on a U.S.-bound flight.

The article said that in recent months, about 91 percent of the people flying to the U.S. without visas had enrolled online but more than four-thousand people a day had not.

The measure is expected to raise controversy in Korea and in other nations.