Fresh cranberries harvested using the dry method at Highland Farms in Troy. Credit: Linda Coan O'Kresik

BRUSSELS — The European Union’s top trade official warned Wednesday that a trade war leaves “no winners” but said the bloc was ready to strike back if President Donald Trump follows through with tariffs on imports of steel and aluminum.

EU trade commissioner Cecilia Malmström also took aim at Trump’s assertion that U.S. national security justified plans to slap tariffs of 25 percent on steel and 10 percent on aluminum.

The U.S. measures “would mainly impact traditional allies of the United States,” she said.

The hardening stance from the 28-nation bloc underscores the global backlash to Trump’s “America First” trade policies and worries that it could ripple through the world economy by triggering reactions from major U.S. trading partners.

Malmström noted that the list for possible EU tariff targets has grown to include some widely consumed American products such as cranberries, orange juice and peanut butter. That comes in addition to the bourbon, motorcycles and blue jeans that EU policymakers have already set in their sights.

“A trade war has no winners,” Malmström told a news conference in Brussels, a clear counterpoint to Trump’s remarks last week that a trade war would be “easy” for the United States to win.

She added that the European Union views the U.S. measures as an economic tool, not as a national security measure. EU leaders, she said, would lodge a complaint with the World Trade Organization if Trump imposes the tariffs.

“We cannot see how the European Union, friends and allies in NATO, can be a threat to international security in the U.S.,” she said. “We find that assumption to be deeply unjust.”

Trump’s plans have set off a furious lobbying campaign in Washington, as well as deep dissent inside the White House and Congress. White House economic adviser Gary Cohn, a staunch opponent of the tariffs, announced his resignation Tuesday, and Defense Secretary Jim Mattis and Secretary of State Rex Tillerson have stood against the plans.

In Brussels, Malmström said that if Trump imposes the tariffs, he would be met with “a firm but proportional response.” The tariffs could cost Europe thousands of jobs, she said.

A draft of European countermeasures circulating in Brussels targets $3.5 billion in annual imports from the United States, including $1.1 billion in U.S. steel products, along with clothing, makeup, motorcycles, boats, corn, rice, beans and other agricultural products.

EU countries exported $6.6 billion in steel and $1.4 billion in aluminum to the United States last year.

Trump singled out the European Union on Tuesday after meeting with Swedish Prime Minister Stefan Löfven in Washington.

“The European Union has been particularly tough on the United States,” Trump said. “It’s been a very, very unfair trade situation.”