More than 100 domestic flights in Japan were grounded on Sunday due to heavy snow in the northern and western parts of the country, Japan’s two biggest airlines said.

ANA Holdings had halted 79 flights as of 4 p.m. (0700 GMT), affecting about 5,100 passengers, said Hiroaki Hayakawa, an operations director for the airline.

Japan Airlines Co had cancelled 49 flights as of 4 p.m. (0700 GMT), affecting 2,460 passengers, a representative with the airline’s operations division said.

Japan, which tightened border controls to counter the threat from Omicron, has reported only about a dozen cases of community spread of the new variant and 231 total Omicron infections, including overseas arrivals, according to the health ministry.

Worldwide, thousands of flights have been cancelled over the Christmas weekend because of the rapid spread of the new Omicron coronavirus variant.