TOKYO — Accusing Russia of failing to live up to its commitments, President Barack Obama warned Moscow today that the United States has another round of economic sanctions “teed up” — even as he acknowledged those penalties may do little to influence Vladimir Putin’s handling of the crisis in Ukraine.

Obama’s pessimism underscored the limits of Washington’s ability to prevent Russia from stirring up instability in Ukraine’s east and exerting influence over elections scheduled for next month in the former Soviet republic.

With no appetite in the U.S. for a military response, Obama is largely banking on Putin, the Russian president, caving under a cascade of economic sanctions targeting his closest associates.

“I understand that additional sanctions may not change Mr. Putin’s calculus,” Obama said during a joint news conference in Tokyo with Japanese Prime Minister Shinzo Abe. “How well they change his calculus in part depends on not only us applying sanctions but also the cooperation of other countries.”

The president’s comments came one week after Russia signed an agreement with the U.S., Ukraine and Europe that called for pro-Russian forces to leave the government buildings they have occupied throughout eastern Ukraine and allow international monitors into the region. But there’s been little indication that Russia is following through on its commitments.

The president said the U.S. has crafted a new package of sanctions to punish Russia for failing to follow through on the Geneva accord, but he stopped short of saying he had, in fact, decided to move forward with those penalties.