Japan on Monday joined Israel and Morocco in barring all foreign travellers, and Australia delayed reopening its borders for two weeks, as more countries sealed themselves off in response to the new Omicron variant of the coronavirus.

The Japanese Prime Minister, Fumio Kishida, said that Japan would reverse a move earlier this month to reopen its borders to short-term business travellers and international students. Japan, the world’s third-largest economy, has been closed to tourists since early in the pandemic, a policy it has maintained even as other wealthy nations reopened to vaccinated visitors.

The emergence of the Omicron variant in southern Africa has left countries around the world scrambling to respond, with some instituting or considering sweeping travel bans, while others have put in place more focused border prohibitions.

Some countries proceeded with their plans to reopen on Monday, like Singapore and Malaysia, which opened their land border. South Korea, on the other hand, said that it was delaying any loosening of social distancing restrictions.