Lawmakers in the European Union are considering a measure that would require Americans visiting member countries in the summer of 2017 to apply for holiday visas in lieu of waivers.

According to Reuters, the proposal came in response to the exclusion of four nations (including Cyprus) from the United States’ visa waiver program:

The European Parliament called on the EU executive to force Americans to apply for visas before visiting Europe this summer, stepping up pressure to resolve a long-running transatlantic dispute on the issue.

The European Commission stressed it was pursuing a diplomatic resolution to the row, leaving it unlikely that it would act on the vote by lawmakers setting a May deadline to impose visas – a move that could hurt Europe’s tourism sector.

Washington refuses to grant visa-free access to people from four east European states and Cyprus, while those from the other 23 member states can enter using the U.S. visa waiver program. EU rules call for equal treatment for all Union citizens.

Quartz offered a more direct summary of the years-long dispute over reciprocity:

The reason […]