WASHINGTON (AP) — The United States and Canada, historic allies along an undefended border, fell deeper into a trade war Saturday marked by angry recriminations and new tariffs that are expected to raise prices for products in both countries.

Each side blamed the other for the collapse of negotiations in Washington late Friday, leading the U.S. to impose 50% tariffs on $20 billion worth of Canadian goods and Canada setting Sept. 8 as the start of its retaliatory penalties.