7.2K views · 157 reactions | A long line of cars formed at the Canada-United States border in Niagara Falls at midnight as Canada began allowing vaccinated U.S. citizens and permanent residents to enter from Monday. cbsn.ws/3jBTaQ4 | CBS Evening News | Facebook

President Trump’s push for Arctic security through Greenland is straining relations with Canada. As tensions rise over the territory and NATO cooperation, sharp remarks have been exchanged by leaders on both sides of America’s northern border. Here's what Kirsten Hillman, Canada's ambassador to the United States, told CBS News' Margaret Brennan. | CBS News