BRUSSELS- The European Union-Russia summit taking place in Yekaterinburg has a major sticking point forming over privacy for travelers arriving -- or even just passing through -- Russian territory.

The Russian Ministry of Transportation has decreed that airlines flying in Russian airspace, or taking off or landing in Russia, have to provide authorities in Moscow with all the information they gather about passengers when the passengers book their trip. That includes credit card numbers, seating preferences, but also addresses and names at their destinations in Russia.

The decree, which goes into effect on July 1, does not distinguish between airplane passengers and those traveling by train, boat or bus. A spokesperson for EU Commissioner for Home Affairs Cecilia Malmström told the Süddeutsche Zeitung that the decree was the cause of "great concern."

If Moscow does not relent, European airlines would find themselves facing a conflict between EU norms and the Russian Federation. EU law forbids airlines to simply turn over the personal data of passengers outside the framework of an agreement such as the one on passenger data signed between the United States and the EU in 2012.

There is much speculation in Brussels for why Moscow has pushed through the measure. Some believe that Russia may, like the US, justify the move in terms of deterring terrorism and crime. Others say it may simply not want to be treated any differently by the EU than the Americans are.

Knut Fleckenstein, a member of the European Parliament, said that the Russian demands were made in the context of long stagnating negotiations about easing visa regulations. If the Russians "put a massive tree trunk" like the data decree in the path of resolution then it sheds doubt on whether Moscow is truly interested in finding a solution to the visa issue, he said. Under no conditions should the Commission relent on this, he added, urging Moscow to rescind the decree at least for the time being so that a viable way forward could be found for both issues.

Russia is not the only country demanding data, said Green member of European Parliament Jan-Philipp Albrecht: Qatar and Saudi Arabia are making the same demand, he said.

Topics at the Yekaterinburg summit include Syria and energy policy alongside the visa issue. Those in the EU delegation include the head of the Commission, José Manuel Barroso, and Energy Commissioner Günther Oettinger.