Six percent of American travelers said they have canceled vacation plans due to fear of further violence following incidents abroad, according to Allianz Global Assistance’s Vacation Confidence Index released Monday.

According to Allianz, recent attacks — including those in Turkey, Brussels, Israel and France — have caused 22% of respondents to alter their vacation plans, including the 6% who said they have canceled. Others said they changed vacation locations (5%), changed travel dates (4%), changed their mode of transportation (4%), changed local tours (4%), changed accommodations (3%) or purchased travel insurance (3%).

The survey revealed that the majority of Americans, 86%, have concerns about terrorist attacks occurring while they are on vacation. They are mostly concerned with potential attacks in the Middle East, followed by Europe and then Africa.

Despite concerns about Europe, Allianz said a flight-booking analysis showed a 10% increase in travel to the continent overall this summer.

“What we’re seeing is that the American traveler is a complex demographic that shares common fears and concerns, but deviate greatly on where they find those fears and how they face them,” said Daniel Durazo, director of communications at Allianz Global Assistance USA.

The Vacation Confidence Index was based off a poll conducted by Ipsos on Allianz’s behalf in May. In total, 2,007 Americans were interviewed online.