Obama, on a visit to the South Korean capital, wants to nudge the European Union towards fresh sanctions against Russia over Ukraine, sources familiar with the matter said earlier.
Obama said he would seek to make sure key European leaders share his view that Russia has failed to live up to the terms of a Ukraine peace deal agreed in Geneva earlier this month.
Discussions with European allies could also set the stage for tougher sanctions on Russia.
"What's also important is laying the groundwork so that if and when we see even greater escalation, perhaps even military incursion by Russia into Ukraine, we're prepared for the sort of sectoral sanctions that would have even larger consequences," Obama said.
Sectoral sanctions refer to broader punitive action targeting specific parts of the Russian economy, such as the defence or energy sectors.
U.S. officials have grown increasingly impatient with what they describe as Russia's failure to follow the terms of the April 17 agreement.
The United States is also frustrated at the reluctance of some European nations, notably Germany and Italy, to impose a new round of economic sanctions on Russia but it would much prefer to act in concert with the EU rather than on its own.
Obama said it had been difficult to achieve consensus among EU member states for a new round of sanctions.
"There's some variation inside of Europe," he said.