A special program meant to help Canadian companies hit by retaliatory tariffs on steel and aluminum imports by the U.S. has started to roll out millions in relief money.

It's the latest incoming trade salvo from the United States: the U.S. is considering punitive duties on pipeline material from a half-dozen countries including Canada.

U.S. aerospace giant Boeing has gone on the offensive, launching a public relations campaign amid its trade battle with Bombardier, to remind Canadians of its economic contribution to the country.