OTTAWA, Jan. 3 (Xinhua) -- Canada on Wednesday denounced the United States for imposing duties on its some softwood lumber exports and underscored its determination to fight against "protectionist trade practices."

"U.S. duties on Canadian softwood lumber are unfair, unwarranted and troubling. They are harmful to Canada's lumber producers, workers and communities," Canadian Foreign Minister Chrystia Freeland said in a statement.

The U.S. Commerce Department accused that Canadian softwood lumber is subsidized and sold in the United States at less than fair value. Ottawa denies it is dumping the lumber.

The anti-dumping and anti-subsidy duties went into effect on Wednesday, ranging from about 10 percent to nearly 24 percent on imports of certain Canadian softwood lumber products, which is commonly used in the construction of homes.

Canada launched two challenges against the duties last year through the World Trade Organization (WTO) and under the North America Free Trade Agreement (NAFTA), the trilateral trade deal between the United States, Canada and Mexico.

The NAFTA dispute panel is expected to make its ruling by fall, while the WTO process could take years.

Freeland said the government of Canada will continue to vigorously defend its industry and its workers against protectionist trade practices.

"Canada will also continue to engage with the U.S. Administration and with American legislators to come to a new agreement on softwood lumber," she added.

The United States is the largest customer for Canadian softwood lumber, while China comes in second place, according to Natural Resources Canada, the federal government's ministry that oversees Canada's forestry sector.

Canada's softwood lumber exports to the United States have fallen since Washington initially enacted its tariffs earlier last year, Canada's national broadcaster, the CBC, reported in December.

The report said the Canadian softwood exports to the United States has fallen by 8 percent in the first nine months of 2017, compared with the same period of 2016.