The US State Department said on Monday it will boost its "Do Not Travel" guidance to about 80 per cent of countries worldwide, citing "unprecedented risk to travellers" from the Covid-19 pandemic.
"This update will result in a significant increase in the number of countries at Level 4: Do Not Travel, to approximately 80 per cent of countries worldwide," the department said in a statement.
The State Department already listed 34 out of about 200 countries as "Level 4: Do Not Travel," including places like Chad, Kosovo, Kenya, Brazil, Argentina, Haiti, Mozambique, Russia and Tanzania. Getting to 80 per cent would imply adding nearly 130 countries.
Most Americans were already prevented from travelling to much of Europe because of Covid-19 restrictions. Washington has barred nearly all non-US citizens who have recently been in most of Europe, China, Brazil, Iran and South Africa.
The State Department said the move does not imply a reassessment of current health situations in some countries, but rather "reflects an adjustment in the State Department's Travel Advisory system to rely more on (Centres for Disease Control and Prevention's) existing epidemiological assessments."
CDC did not immediately comment.
Earlier this month, the CDC said people who are fully vaccinated against Covid-19 can safely travel within the United States at "low risk" but CDC Director Rochelle Walensky discouraged Americans from doing so because of high coronavirus cases nationwide.
"We know that right now we have a surging number of cases. I would advocate against general travel overall," Walensky said. "We are not recommending travel at this time, especially for unvaccinated individuals."