Russia expels Austrian diplomats in retaliation.

On Thursday, Russia announced it was expelling four Austrian diplomats in a retaliatory move after Vienna expelled four Russian diplomats. The Austrian diplomats had been given a week to leave after being accused of behaving in a way that violated international agreements.

In a statement, Russia’s Foreign Ministry condemned Austria’s “unfriendly and unjustified step,” and said it was ruining Austria’s previous status as a respected, neutral state. Austria has yet to provide details on why the diplomats were expelled.

The Austrian Foreign Ministry said in response to Russia’s move, “We regret this unjustified decision by Russia, which lacks any basis in fact.” The ministry also stated that the diplomats were operating within the Vienna Convention on Diplomatic Relations.

Vienna is a major diplomatic hub, hosting the Organization for Security and Cooperation in Europe (OSCE) and several United Nations organizations. As a result, many countries, including Russia and the United States, have separate ambassadors to Austria, the OSCE, and the U.N. organizations, each running an embassy or permanent mission. Vienna is also known for its espionage activity, as the large diplomatic presence provides a cover for intelligence agents.

While Austria only has a dozen diplomats based in Moscow, more than 140 Russian diplomats are listed as working in Vienna.