More than two weeks in, the government shutdown is already hurting business travel, and insiders expect the impact to grow more severe if the impasse continues.

According to a poll conducted by the Global Business Travel Association, a third of respondents said they have already seen repercussions from the partial shutdown, which started Dec. 22. President Donald Trump and Congress have been unable to reach a deal to reopen the government because he is insisting on $5.7 billion in funding for a controversial border wall.

On Monday and Tuesday, the business travel advocacy group conducted an online survey of 409 members, including buyers and suppliers.

Nearly half of those who responded said they had dealt with canceled bookings and concern from travelers about airline delays and cancellations. Airport security delays had hit 45 percent, while nearly 40 percent reported canceled meetings or business opportunities in the United States as well as greater uncertainty about the economy.

Two-thirds of respondents said they expect a negative impact if the shutdown stretches past the end of the week.

“With more than two-thirds of our members concerned about a negative impact if the shutdown continues, the widespread impact on the business travel industry is undeniable,” Michael McCormick, the association’s executive director and chief operating officer, said in a statement. “Given the importance of business travel as an economic driver, it is imperative that Congress works to resolve this issue before it leaves a lasting negative impact on the U.S. economy.”

The U.S. Travel Association said last week that according to preliminary estimates, the shutdown is resulting in lost economic output of more than $100 million a day just for travel.

Baked into that number is $50 million in direct domestic travel spending. The estimate also counts more than $50 million in indirect or induced output related to national park closures, a halt of some government travel, and the loss of additional government-related business travel.

Photo Credit: A TSA agent screens travelers inside Ronald Reagan National Airport in Arlington, Virginia on Dec. 24, 2018. Photographer: Zach Gibson/Bloomberg