Concern among some big European nations about economic fallout raises the risk of a split with the U.S. on how strongly to hit Russia with fresh sanctions if it invades Ukraine, according to people familiar with the matter.

Western allies are united in their desire to prevent a war as they enter high-stakes talks this week aimed at defusing tensions with Russia, warning it faces massive penalties for any incursion. Actions that have been discussed include export controls, curbing Russia’s access to technology, and even cutting it out of the global system for financial payments.

But while the major Western European members of the European Union remain committed in principle to a significant response, some have also aired worries with the U.S. about the potential for damage to their own economies, the people said. The group is still working through economic and legal assessments of the potential sanctions, they said.