WASHINGTON/MEXICO CITY (Reuters) - Mexican tariffs are roiling U.S. congressional campaigns in states where U.S. exporters could take a hit and President Donald Trump’s Republicans face tough races in November congressional elections.

Apples for sale are pictured inside a Whole Foods Market in the Manhattan borough of New York City, New York, U.S. June 16, 2017. REUTERS/Carlo Allegri

Mexico announced the levies this week in retaliation to Trump’s decision to slap tariffs on metal imports from Mexico and other countries. They fall on only about $3 billion in U.S. exports, but were crafted to have a “very specific” focus on vulnerable Republicans, said one senior Mexican official who asked not to be named.

“We wanted to ensure that the issue is a top priority for key decision makers at the highest level,” said another Mexican official who requested anonymity.

The tariffs could hit American apple growers in Washington state, cheesemakers in California and pork producers in Iowa, Virginia and Colorado.

Apples are grown in Washington’s 8th congressional district, where U.S. Representative Dave Reichert, a Republican, is retiring. Mexico slapped a 20 percent tax on fresh U.S. apples, and Democratic candidate Kim Schrier hammered her Republican opponent, saying the local economy will suffer.

Apples are one of 71 U.S. products targeted by Mexico, which is also in talks with the United States and Canada to renegotiate the North American Free Trade Agreement. Last year, Washington state exported $126 million in fresh apples to Mexico, paying zero tariffs thanks to the NAFTA agreement.

“I hold Republican opponent Dino Rossi accountable for President Trump’s dangerous policies,” said Schrier. However, Rossi, the Republican frontrunner since Reichert announced his retirement, has distanced himself from Trump’s trade policies. His campaign manager, Andrew Bell, said: “Dino supports removing trade barriers that tax Washington farmers, consumers and businesses.”

Roughly three dozen House races are widely seen as competitive this year. Democrats need to pick up 23 seats to take control of the House.

Mexico’s tariffs also target several types of pork products. Pork, one of America’s top exports to Mexico, is a major export from Iowa and Colorado, where Republicans face tough races.

In Iowa, pigs outnumber people seven to one. Democrat Abby Finkenauer, seen standing a good chance of winning the 1st congressional district from Republican control, said Trump was starting a trade war that would hurt the state.

Colorado sent Mexico more than $120 million in fresh or frozen bone-in pork shoulders last year.

“Mexico’s retaliatory tariffs will hurt Coloradans, and the blame here lies squarely with President Trump and the Congressional Republicans who enable his destructive policies,” said Jason Crow, a Democratic candidate for the state’s 6th congressional district.

Crow said the district’s Republican incumbent, Mike Coffman, shares blame in triggering Mexican tariffs. Coffman’s campaign manager, Tyler Sandberg, disputed the charge, saying that Coffman opposed Trump’s actions to raise tariffs on Mexico and other countries.

Mexico’s tariffs also target grated or powdered cheese, which could take a bite of the significant dairy economy in California’s 10th congressional district where Republican Jeff Denham is seen facing a tight race.

California sent Mexico $77 million in grated or powdered cheese last year, according to U.S. Census Bureau data. About 10 percent of the state’s milk output comes from Stanislaus County, which is in the 10th congressional district, according to data from the California Department of Agriculture.