Travel to Paris, Rome, and other popular destinations might get trickier for U.S. nationals.

The European Parliament voted Thursday to end the visa waiver program with the U.S., citing the U.S. lack of reciprocity, Reuters reported.

U.S. nationals have long been able to travel throughout Europe without needing a visa for stays less than 90 days. The U.S., along with Australia and Canada, however, continued to require visas for five EU member states: Bulgaria, Croatia, Cyprus, Poland, and Romania. The State Department cited security concerns for these countries, saying they did not meet the requirements for the U.S. visa waiver program.

The vote from the European Parliament is widely seen as a retaliatory move against the U.S., as Australia and Canada agreed to a 2014 EU request to lift visa requirements for at least some of these countries. Under EU law, action must be taken two years after a visa reciprocity request, triggering the vote this week.

A whopping 12.6 million U.S. citizens traveled to Europe in 2016, according to data from the U.S. National Travel and Tourism office. Some European lawmakers fear that reinstating visa requirements will slow the flow of visitors to the EU and cost the bloc millions in revenue.

“The effect of terrorism in Europe in recent years emphasized how fragile our appeal is as a destination in long-haul markets," István Ujhelyi, member of European Parliament and chair of the tourism task force, told the Telegraph. “This is not a time to put unnecessary obstacles in the way of one of the sectors most capable of generating employment," he said.