U.S. President Donald Trump said Wednesday he delayed tariffs on some Canadian goods for three days because he believes Washington and Ottawa have reached a trade deal, as negotiations advance toward sharply lower duties on Canadian-made vehicles, steel and aluminum.

"We delayed it for three days because I think we have a deal with the Prime Minister and (a) good deal for everybody. So that's good," Trump told reporters.

A U.S.-Canadian trade deal still under negotiation is expected to cut Trump's top-line tariff rates on Canadian-built cars and trucks to 15% from 25% and halve the top-line tariff rates on Canadian steel and aluminum to 25%, a source familiar with the talks said.

The reduction in steel tariffs is also expected to come with a volume quota arrangement, but details were not immediately available. The 15% top-line autos tariff also would come before deductions for the value of U.S.-produced content, bringing the effective rate substantially lower, the source told Reuters.

Negotiations over the emerging deal, which staved off new 50% U.S. tariffs on Wednesday, are expected to continue ahead of a new deadline at 12:01 a.m. EDT (0401 GMT) on Saturday and the details could change.