Earlier this month President Trump signed a revised executive order banning citizens from six Muslim-majority nations from traveling to the US.

"The travel ban is not having a material impact yet. But we are seeing the unintended consequences of this now because the message has gone around the world that the US is not open for business," WTTC’s president David Scowsill told Reuters.

The travel and tourism sector’s contribution to the US gross domestic product (GDP) is expected to grow by 2.3% this year, a slowdown from an expansion of 2.8% seen in 2016, WTTC said on Monday.

“Overall the US is still robust,” Scowsill continued. “The most important thing is that we get to the end of this (travel ban) situation.”

The U.S. travel and tourism sector is the biggest in the world, accounting for $1.5 trillion, or around 20 percent of the world’s travel and tourism GDP contributions.