Moscow would have its access to financial markets and high-tech goods limited under Western sanctions being prepared in case Russia attacks Ukraine, one of the European Union’s top officials said Saturday.

The comments from Ursula von der Leyen, the head of the EU’s executive commission, came as tensions over Russia’s intentions toward Ukraine intensified. U.S. President Joe Biden said Friday he was convinced” Russian President Vladimir Putin has decided to invade the neighboring country.

“The Kremlin’s dangerous thinking, which comes straight out of a dark past, may cost Russia a prosperous future,” von der Leyen said Saturday during the annual Munich Security Conference, where U.S. Vice President Kamala Harris also spoke.

Von der Leyen said the EU’s executive arm has developed a “robust and comprehensive package” of financial sanctions with the U.S., U.K. and Canada.

“In case that Russia strikes, we will limit the access to financial markets for the Russian economy and (impose) export controls that will stop the possibility for Russia to modernize and diversify its economy,” she added. “And we have a lot of high-tech goods where we have a global dominance, and that are absolutely necessary for Russia and cannot be replaced easily.”

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German Chancellor Olaf Scholz said that during a Tuesday meeting with Putin he “made clear that any further violation of the territorial integrity of Ukraine will have high costs for Russia, politically, economically and geo-strategically.”

“And at the same time, I stressed that diplomacy won’t fail because of us,” Scholz added. “As much diplomacy as possible without being naïve, that is our aspiration, and we are using all channels of communication for that.”

Western leaders so far have not specified what precise Russian action would trigger sanctions. A French official who wasn’t authorized to be publicly named and spoke on condition of anonymity after Biden conferred with several counterparts on Friday said they were talking about an invasion of territory currently under the control of the government in Kyiv.

“It is in the event of an invasion of this territory that ... the massive sanctions that we are talking about would be triggered,” the official said.

Parts of eastern Ukraine are under the control of pro-Russia separatists who have been fighting Ukrainian forces since 2014, the year Russia annexed Ukraine’s Crimean Peninsula.

German Foreign Minister Annalena Baerbock, asked what Russian actions would trigger sanctions, didn’t offer any details after a meeting in Munich with her counterparts from the Group of Seven industrial powers and Ukraine.

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“A breach of Ukraine’s integrity and sovereignty is a breach of Ukraine’s integrity and sovereignty,” Baerbock said. “You can’t say that one geographical part is a bit more Ukraine and another is a bit less Ukraine.”

She said Western officials have made clear that an actual invasion isn’t the only possible scenario but “are prepared for every situation.” Using a chess analogy, the German minister said, “If you present your next five moves in public, you won’t be particularly successful.”