The US has imposed 50% tariffs on some goods from Canada, and Mark Carney, the country’s prime minister, has vowed to match them “dollar for dollar” after the collapse of trade talks.

The tariffs came into force on roughly $20bn (£14.6bn) of goods – ranging from hockey sticks to tongue depressors – at 04.00GMT. Trade experts said the tariffs could result in some job losses, but the largest impact is expected to be political, driving a further wedge between the traditional allies.

The trade row is the biggest rupture in recent relations between Washington and one of its closest allies and trading partners as Trump’s bellicose foreign policy angered officials in Ottawa. US officials accused Canada of collapsing the deal by seeking additional concessions at the last minute. The US tariffs will affect about $20bn worth of Canadian products, and the US trade representative, Jamieson Greer, said the breakdown represented a “missed opportunity for Canada”.

The two sides appeared close to a deal on Friday to lower tariffs on steel, aluminium and cars, but the deal was scuttled at the last minute. The two sides blamed each other for the collapse.

Canadian officials had worked hard in good faith but “last-minute changes in the US proposed terms were unfair, uneconomic and called into question the reliability of any deal”, Carney said in a statement. Carney recalled his negotiators as Canada vowed to match Washington’s tough approach. No further talks are planned.

The owner of a large dog suspected of mauling two smaller dogs to death in Yuen Long has been arrested.

The Agriculture, Fisheries and Conservation Department (AFCD) in Hong Kong said in a statement on Tuesday night that it had arrested the owner of the dog earlier that day and collected a statement regarding the case.

The recent incident happened on Monday, when an unaccompanied Tibetan Mastiff bit a Bichon Frisé and did not let go. It occurred at the pet-friendly Dot Park outside Yoho Mall in Yuen Long, according to an online video. Around 20 minutes before the Bichon Frisé was attacked, a poodle was also allegedly attacked by the same canine at a public transit hub near the mall, police told local media.

On Wednesday, Jackie Yip, an assistant director of the Agriculture, Fisheries and Conservation Department (AFCD) said the authorities were discussing with the owner as to whether to keep the dog or place it in the care of the government.

The AFCD added that the dog was previously detained by the department in July due to another dog attack case, but the animal was then returned to its owner, who was warned to keep it on a leash no longer than two metres in public places.

If a dog is declared a “known dangerous dog” in Hong Kong, it must be desexed, muzzled and leashed in public and wear a specific, government-approved collar. A magistrate can also rule that a dog that is a public hazard be destroyed humanely.

Tibetan Mastiffs are a highly territorial breed and may attack other dogs. It is understood that the dog owner regretted signing the abandonment agreement, saying that he did not understand that “disposal” meant humane euthanasia. He also said that “Larry” was docile and affectionate, and hoped that the abandonment could be cancelled to save his precious life.

Harry and Meghan Markle, the Duke and Duchess of Sussex, are planning to move back to the UK this month, as reported by ABC.

They intend to relocate from the US to a private, non-royal residence outside London. The couple’s children, Archie, seven, and Lilibet, five, are also expected to start at a British school in September.

British media first reported the news, but spokespeople for ⁠Harry and Meghan had no immediate ‌comment. However, a source close to the couple confirmed the report’s accuracy. King Charles was told of the move on Sunday, local time, and it is understood he welcomed the move.

Earlier in July, the family met with King Charles in what was widely seen as a thawing of frosty relations. But even the run-up to the July trip was rocked by setbacks, with media outlets quoting sources close to Harry as saying the prince would be staying at Buckingham Palace in London — only for the palace to deny it.

The palace also said Harry had not accepted the invitation to stay at the official residence of the British sovereign sufficiently far in advance. It has been six years since Harry and Meghan stepped down from their royal duties, and there are no public plans for either to resume those roles.

Harry has long blamed the media for the death of his mother, Princess Diana, who was killed in a Paris car crash in 1997 while trying to shake off the paparazzi. While Harry and the king’s relationship may have improved, he is still barely on speaking terms with his older brother, Prince William.