President Obama tried Friday to showcase unity with German Chancellor Angela Merkel on potential stronger sanctions against Russia, saying that Western nations would have no choice but to impose wider-ranging penalties against the Russian economy if the Kremlin disrupts the Ukrainian elections later this month.

“The next step is going to be a broader-based, sectoral sanctions regime," said Obama, joined by Merkel in the White House Rose Garden.

“We will not have a choice but to move forward with additional, more severe sanctions,” he said of the prospect of the Russians interfering with elections planned for May 25.

For her part, the German chancellor said she would prefer to avoid additional sanctions against Russia but added that they may be “unavoidable” if Russian President Vladimir Putin doesn't change course in Ukraine.

To successfully deter Putin from further incursions into Ukraine, Obama will need the support of major European allies, particularly Merkel -- the leader of the strongest economy in Europe.

The White House has issued sanctions against senior Russian officials and businesses with close ties to Putin but has resisted going after the Russian energy sector and other areas that would carry significant blowback for European economies highly dependent on Russia's oil and gas.

As the two leaders discussed the showdown with Russia, clashes in Eastern Ukraine intensified. The Kiev interim government started a coordinated effort to remove pro-Russian sympathizers from the region, which drew a strong rebuke in Moscow.

But Obama accused Putin of not engaging in honest negotiations with leaders in Kiev about a path forward in the wake of the annexation of Crimea.

“If the Russian leadership does not change course, it will face increasing costs,” Obama pledged.

Still, both leaders were reluctant to commit to specific economic punishments against Russia.

Analysts have focused in particular on hitting the Russian energy sector, the foundation of the nation’s economy. But such sanctions would also create significant problems for Europe.

Obama on Friday seemed to highlight the limitations of such penalties.

“The idea that you’re going to turn off the tap,” Obama said of Russia’s oil and gas sector, “I think is unrealistic.”

This article was published at 1:02 p.m. and has since been updated.