Commerce Secretary Gina Raimondo on Wednesday urged U.S. tourism companies to require their employees to get vaccinated against the coronavirus as pandemic-induced travel restrictions continue to hobble the industry.

Some travel businesses not affected by President Biden’s new vaccination requirements for medium and large companies have still chosen to mandate the shots for their workers, Raimondo told the U.S. Travel and Tourism Advisory Board.

“They’ve seen significant increases in their vaccination rates because of their company policies, and we applaud those decisions,” she said to the 32-member committee gathered in Washington. “We encourage you all to consider doing the same.”

Raimondo also asked the companies to “think creatively” about how to get their customers vaccinated so remaining barriers to international and business travel can fall.

The secretary’s remarks followed comments from White House coronavirus response coordinator Jeff Zients, who told the board that the Biden administration may require vaccinations for non-U. S. citizens traveling to the United States. White House officials debated including such a requirement in last week’s new vaccination mandates, but decided against it for now. A broader vaccine mandate including domestic air travel is also under consideration.

“This one of the paths being considered, but there are alternative paths being looked at, as well,” Zients said Wednesday of a vaccination mandate for foreigners.

Zients said the Biden administration also plans to implement contact tracing for international visitors who have been exposed to the coronavirus, and intends to strengthen the United States’ testing and surveillance. He stressed that the administration has no plans to imminently loosen restrictions on international travel as the highly contagious delta variant surges around the world.

White House press secretary Jen Psaki added that the administration’s goal is to make its international travel policies clearer, equitable and more consistent.

“The current rules have been quite confusing — or the rules that have been in place for some time,” she told reporters.

The White House has been discussing a vaccination requirement for foreign visitors since at least midsummer, Reuters reported at the time.

Air carriers have increasingly mandated immunization. After United Airlines implemented a vaccine requirement in August, the company announced that employees who receive religious or medical exemptions would have to take temporary leave.

Delta Air Lines requires employees who are not vaccinated to pay a $200 monthly insurance surcharge. Frontier and Hawaiian airlines also compel the shots.

Since January, all travelers entering the United States have been required to show a negative coronavirus test taken within three days of departure or proof that they have recovered from the virus in the past 90 days. Most non-U. S. citizens who in the past 14 days have been in any of 33 countries — including China, India, the United Kingdom and Ireland — are barred from entering the U.S.

The United States also bans noncitizens from crossing the land borders with Canada and Mexico for “nonessential” reasons.