As COVID-19 infection rates fall and Europe’s traditional summer holiday season begins, borders between countries in the European Union are starting to open up again—but in a very patchwork fashion. And that is worrying the EU’s top officials.

Some internal EU borders have already reopened, including between Austria and the Czech Republic. A bunch more are set to follow at the start of next week, when heavyweights such as France and Germany will start letting in people from any other EU country. But certain countries, such as Hungary and Denmark, are set to leave some of their borders closed for now.

The European Commission, which is desperate to help the bloc keep its tourism industry alive, is not happy. On Thursday it renewed its call for member states to coordinate their openings—not just for the sake of the EU’s crucial freedom of movement, but because doing so will make it easier to then reopen the EU’s external borders.

“Several member states [have] already lifted restrictions within the EU and others [plan] to do so as of 15 June 2020. The Commission strongly encourages the remaining member states to finalize the process of removing restrictions to free movement and lifting internal border controls within the EU by 15 June 2020,” the EU executive body said.

As for how the EU lifts restrictions on people arriving from the rest of the world, the Commission is again calling for more coordination. After all, if people can travel freely within the EU then it makes little sense for different EU countries to have their own ideas about which countries’ citizens are safe for entry and which are not.

“Following the lifting of all internal border checks inside the Union, we are proposing a clear and flexible approach towards removing restrictions on travel to the EU starting on 1 July,” said Ylva Johansson, the Commission’s home affairs chief.

“International travel is key for tourism and business, and for family and friends reconnecting. While we will all have to remain careful, the time has come to make concrete preparations for lifting restrictions with countries whose health situation is similar to the EU’s and for resuming visa operations.”

The Commission had previously recommended that the closure of the EU’s external borders expire on June 15, but some countries—such as Estonia—remain very cautious about who they let in. EU countries’ interior ministers agreed at a Friday meeting that the bloc’s border will stay shut until June 30 at the earliest.