President Obama gave Russian President Vladimir Putin a May 25 deadline for suspending efforts to destabilize eastern Ukraine, lest the United States and the European Union impose broad economic sanctions on the Russians.

"The next step is going to be a broader-based sectoral sanctions regime," Obama told reporters during a joint news conference with German Chancellor Angela Merkel on Friday. "If, in fact, we see the disruptions and the destabilizations continuing so severely that it impedes elections on May 25, we will not have a choice but to move forward with additional, more severe sanctions."

The sanctions would hit "a range of sectors" in the Russian economy, keeping in mind that some sanctions could also harm European countries.

"The goal is not to punish Russia, the goal is to give them an incentive to choose the better course, and that is to resolve these issues diplomatically," Obama said.

During a news conference in South Korea last Friday, Obama had threatened broader sanctions if Russia invades Ukraine, saying, "If and when we see even greater escalation, perhaps even military incursion by Russia into Ukraine, that we're prepared for the sort of sectoral sanctions that would have even larger consequences."