OTTAWA, Sept 15 (Reuters) - Canada will unveil retaliatory tariffs on a range of U.S. goods on Tuesday after Washington moved to impose punitive measures on Canadian aluminum imports, Prime Minister Justin Trudeau said.

Deputy Prime Minister Chrystia Freeland will make the formal announcement at 3 p.m. ET (1900 GMT), her office said.

Ottawa said last month it would impose sanctions on C$3.6 billion ($2.7 billion) worth of U.S. aluminum and products containing aluminum.

"We will be taking action to counter the unjust tariffs put on Canadian aluminum by the United States," Trudeau told reporters before a Cabinet retreat in Ottawa.

Canada, like Mexico, sends around 75% of its goods exports to the United States. The three nations signed a new continental free trade pact in late 2018.

But this August, U.S. President Donald Trump said he would reimpose 10% tariffs on some Canadian aluminum products to protect U.S. industry from a "surge" in imports. Canada denies any impropriety.

Ottawa slapped tariffs on a wide range of U.S. goods in 2018 after Washington imposed sanctions on Canadian aluminum and steel. The Trump administration lifted the measures in 2019. ($1=1.3153 Canadian dollars)