OTTAWA — The United States extended its restrictions on non-essential travel at land and ferry border crossings yet again on Friday, the first such extension since Canada welcomed vaccinated Americans back into the country earlier in the month. 

The U.S. borders will remain closed to most travellers until at least Sept. 21, the U.S. Department of Homeland Security said in a tweet.

"To minimize the spread of (COVID-19), including the Delta variant, the United States is extending restrictions on non-essential travel at our land and ferry crossings with Canada and Mexico ... while continuing to ensure the flow of essential trade and travel," it reads. 

The restrictions, which have been in place since March 2020, were set to expire Saturday. 

The U.S. does, however, allow Canadians to fly across the border for non-essential purposes. 

The Canadian government eased the 17-month long ban on non-essential travel across the Canada-U.S. border on Aug. 9.

Canada currently allows U.S. citizens and permanent residents into the country, provided they've been fully vaccinated against COVID-19.

Eligible visitors to Canada must live in the U.S. and have allowed 14 days to pass since receiving a full course of a Health Canada-approved vaccine.

They are also required 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 web portal to upload their vaccination details. 

The lopsided policy has rankled observers on both sides of the border.

"This creates confusion for travellers when all our members repeatedly tell us they are seeking predictability. This also distracts from the efforts that should be put into developing interoperable digital health credentials," said Mark Agnew, senior vice-president of policy with the Canadian Chamber of Commerce.

But campaigning Liberal Leader Justin Trudeau said some unevenness is inevitable. 

"We will work together as much as possible to co-ordinate and make sure things are going well, but every country gets to make its own decision about how to keep their citizens safe," he said. 

Conservative Leader Erin O'Toole, meanwhile, said a combination of rapid testing and vaccines should be enough to safely reopen borders, suggesting a foundering relationship with the U.S. was to blame for the stricter American policy. 

"In the past few years under Mr. Trudeau, our relations with the United States has been in serious decline," O'Toole said. "We will re-establish those ... solid relations." 

Elsewhere, NDP Leader Jagmeet Singh said since he grew up in Windsor, Ont., he knows how hard the border closures have been on residents with many personal and professional connections in Detroit.

"With any decision around whether we open or close the borders, I again want to make sure that we are relying on the best evidence from public health and following the best course of action that protects Canadians," he said. 

This report by The Canadian Press was first published Aug. 20, 2021. 

The Canadian Press