LUXEMBOURG — European Union foreign ministers will hold talks on Monday to discuss how to toughen sanctions against Russia for its actions in Ukraine without losing the support of some EU governments worried about antagonizing a power with an energy stranglehold over Europe.

Under discussion are possible new economic sanctions, as well as an EU mission to train police and other law-enforcement officials in Ukraine and the bloc’s approach to issuing visas and trade with the Crimean peninsula, which was annexed by Moscow in March after popular protests toppled pro-Russian president Viktor Yanukovych.

Tensions between Russia and Ukraine escalated over the weekend, with Kiev announcing plans for a “full-scale anti-terrorist operation” against a rash of rebellions in eastern Ukraine that it says are inspired and directed by the Kremlin.

The U.S. Treasury Secretary Jack Lew said Friday that the Group of Seven leading rich nations would support increasing sanctions against Russia if Moscow escalates the crisis in Ukraine.

But a senior EU official said Friday that any wide-ranging economic measures would not be ready by Monday, with the bloc’s 28 governments focusing on diplomatic efforts to calm tensions later in the week. EU foreign policy chief Catherine Ashton is due to meet officials from the U.S. Russia and Ukraine in Geneva on Thursday.

“The real question will be to see whether [EU] member states agree to ask [Ashton’s office] to prepare an additional list of restrictive measures,” he told reporters.

It is unclear what areas of the Russian economy, if any, could be subject to future EU sanctions. One EU diplomat said, however, that the bloc could agree on Monday to add names to a list of Russian and Crimean officials targeted by EU asset freezes and visa bans over Moscow’s takeover of the peninsula.

In talks with industry representatives and officials from Ukraine last week, the EU’s Energy Commissioner Guenther Oettinger said natural gas, Russia’s key export product, would not be part of any sanctions, according to minutes of a closed-door meeting in Brussels seen by Reuters.

The EU is highly dependent on Russian gas deliveries, and the crisis over Ukraine has fanned concerns about future supply.