The US State Department has loosened travel warnings for more than 100 nations, including France, Germany and Canada, as the coronavirus pandemic wanes in many places.
Japan is also included in the eased advisories before the Tokyo Olympics, amid a growing controversy over holding the Games while the country is facing a new wave of Covid-19 cases.
The department changed its travel warnings on Tuesday for many nations from Level 4, or “Do not travel”, to Level 3, or “Reconsider travel”, its website said.
It said it was updating the advisories after the US Centres for Disease Control and Prevention changed the system for travel health notices.
The CDC said the new criteria for a Level 4 recommendation changed from 100 Covid-19 cases for every 100,000 people to 500.
Countries affected by the latest changes also including Mexico, South Korea and Singapore.
The CDC said it also revised its rating for the US from Level 4 to Level 3.
On May 24, the State Department urged residents against travelling to Japan because of a new wave of coronavirus cases before the Olympics are set to begin on July 23.
The State Department warning raised concerns and prompted the White House to reaffirm its support for Tokyo's plan to hold the Olympics this summer.
Foreign spectators have been banned from the Games and organisers are expected to make a decision this month on the presence of Japanese spectators.
The advisories are not binding but can help airlines and other nations to set their own restrictions for travel.
The move comes days before President Joe Biden plans to visit the UK for a Group of Seven meeting and as Vice President Kamala Harris visits Mexico.
Airlines and some nations have complained that travel restrictions to the US are out of step with rising vaccination rates and the reduced threat of contracting Covid-19.
”We have heard very clearly the desire of our friends in Europe and the UK to be able to reopen travel across the Atlantic Ocean, and we want to see that happen,” National Security Adviser Jake Sullivan said on Monday.
“But we have to follow the science and we have to follow the guidance of our public health professionals. We’re actively engaging them to determine the time frame.”
In the US, new infections are at the lowest level since the pandemic began in March 2020.
Weekly cases worldwide have been declining for six weeks as the outbreak in India wanes and global vaccination efforts increase.
Many of the countries that now have lower ratings remain on the US government's list of those subject to severe travel restrictions, with most having been on the list since early 2020.
The US bars nearly all non-American citizens who have travelled within the previous 14 days to China, the UK, Ireland, India, South Africa, Brazil, Iran and the 26 Schengen countries in Europe, which have no border controls.
CDC director Dr Rochelle Walensky explained on Tuesday why the US was maintaining the warnings for some countries with lower infection rates while others with high rates were exempt.
Dr Walensky said the issue was subject to "an interagency conversation and we are looking at the data in real time as to how we should move forward with that".
The US has also been in discussions with Canada and Mexico on how to eventually lift or revise restrictions at US land borders that bar non-essential travel.