TORONTO -- The United States is extending restrictions on non-essential travel across its land and ferry borders with Canada and Mexico until Sept. 21.

The U.S. Department of Homeland Security tweeted Friday that the measures remain in place to “minimize the spread of COVID-19, including the Delta variant.”

Fully vaccinated Americans have been able to enter Canada for non-essential visits since Aug. 9.

“In co-ordination with public health and medical experts, DHS continues working closely with its partners across the United States and internationally to determine how to safely and sustainably resume normal travel,” the department said.

Some Canadians, especially those with loved ones in the U.S., have expressed frustration that they are still unable to drive across the border for a visit.

Air travel to the U.S. is allowed with certain conditions, including proof of a negative COVID-19 test or proof that the traveller has recovered from a COVID-19 infection in the past 90 days.

The restrictions on non-essential travel at the U.S. border have been in place since March, 2020.

Liberal Leader Justin Trudeau told reporters on the federal election campaign trail Friday that “there's always been a certain asymmetry in the arrangements” between Canadian and U.S. border restrictions throughout the pandemic.

“Canadians unvaccinated or vaccinated have always been able to fly down to Florida or Arizona over Christmas, when we weren't reciprocating for Americans who wanted to come up to the cottages or for more … in Canada,” he said, noting that the Canadian government is co-ordinating “closely” with the U.S. administration on border issues. 

“So, we will work together as much as possible to co-ordinate, make sure things are going well, but every country gets to make its own decisions,” he said.

Now that restrictions have been eased on the Canadian side of the border, visiting Americans must be fully immunized with one of the four COVID-19 vaccines approved by Health Canada: Pfizer-BioNTech, Moderna, the Oxford-AstraZeneca shot, also known as Covishield, and the single-dose Johnson & Johnson.

They also have to show proof of a negative molecular test for COVID-19 that's no more than 72 hours old and use the ArriveCAN app or online portal to upload their vaccination details.

The U.S. government has been criticized for its approach to the land border restrictions in recent months, with such politicians as New York Rep. Brian Higgins saying that keeping them in place "harms separated families and hurts opportunities for economic recovery.”

The Canadian Chamber of Commerce said Friday it is “disappointed to see the continued restrictions on the land border going into the United States given both the opening of the border to fully vaccinated Americans coming into Canada and the ability of Canadians to fly into the U.S. for all purposes.”

In a statement to, the chamber’s senior vice president of policy, Mark Agnew, said this “creates confusion for travellers when all our members repeatedly tell us they are seeking predictability.”

Agnew said efforts should be put into developing “interoperable digital health credentials” that can be used for cross-border travel.

With files from The Canadian Press and's Rachel Aiello