According to a Feb. 27 report from research firm Tourism Economics, visits are expected to fall 5.1%, down from an earlier view for an 8.8% increase. Spending by foreign tourists is expected to tumble 11%, representing a loss of $18 billion this year.

That’s as President Trump’s tariffs and friendlier approach to Russia have created a global backlash, while an expanded trade-war scenario is seen slowing economic growth across U.S. trade partners and weighing on their currencies.

“In key origin markets, a situation with polarizing Trump Administration policies and rhetoric, accompanied by economic losses to nationally important industries, small businesses and households, will discourage travel to the US,” the report said. “Some organizations will feel pressure to avoid hosting events in the US, or sending employees to the US, cutting into business travel.”

In emailed comments to Fortune, Tourism Economics President Adam Sacks said in the two weeks since the report came out, the situation has deteriorated further and the forecast for a 5.1% decline is likely to get worse.

Visitors from Canada, which has been hit by Trump’s tariffs and demands for it to become the 51st U.S. state, have been canceling travel plans. In fact, the number of Canadian car trips coming back from the U.S. were down 24% in February compared to a year ago, and overall travel from Canada is seen falling 15% this year.

Meanwhile, Trump’s immigration crackdown may also raise concerns among potential travelers, particularly from Mexico, the report added.

Travel from Western Europe, which accounts for over a third of foreign tourism to the U.S., is susceptible to declines due to tariffs and “the administration’s perceived recent alignment with Russia in the war in Ukraine as sentiment towards the US is damaged,” Tourism Economics warned.

Separate data shows the overall number of foreign visitors to the U.S. fell 2.4% last month from a year ago. Travel sank 9% from Africa, 6% from Central America, and 7% from Asia, with China down 11%, according to a Washington Post analysis of government statistics.

Airlines have also sounded the alarm recently on lessened travel demand from consumers and businesses as tariffs and mass federal layoffs create economic uncertainty.

Not only are tariffs slamming foreign tourism, they are widely expected to slow U.S. economic growth, with Wall Street pricing in growing odds of a recession.

And fewer overseas visitors will make that worse because all their spending in the U.S. is treated in government statistics like an export, meaning the trade deficit is poised to widen. A deeper imbalance was a major factor in the Atlanta Fed’s GDP tracker suddenly shifting into negative territory for the first quarter.

To be sure, similar declines in foreign visitors were seen during Trump’s first term, especially from Mexico, China, and the Middle East, according to Tourism Economics. But his trade war was more limited back then. Now, his tariffs are more aggressive and expansive, with no sign he plans to back down.

That comes as the U.S. will feature prominently in major upcoming tourism events. The U.S. will co-host the World Cup next year, and Los Angeles will host the Summer Olympics in 2028.

Sacks told Fortune the World Cup is less likely to be affected while the Olympics may be more at risk comparatively.

“The issue for general holiday travelers is that they have a choice of when and where to travel,” he added. “This ultimate discretion means that antipathy towards a country’s leadership can have appreciable effects.”