The U.S. and Canada have ramped up their trade war, hitting each other with steep new tit-for-tat tariffs.

Canadian Prime Minister Mark Carney accused US President Donald Trump of initiating a trade war after negotiations between Washington and Ottawa collapsed on Friday.

Canadian Prime Minister Mark Carney has announced retaliatory tariffs on the United States, after walking away from a "bad deal" on trade in a deepening rift between the longtime…