WASHINGTON -- President Barack Obama on Thursday expanded U.S. economic sanctions against Moscow, targeting 20 individuals inside and outside the government, as well as a Russian bank that provides them support.

Obama, warning of more costs to come for the Kremlin because of its actions in Ukraine, said he also signed an executive order that would allow the U.S. to penalize key sectors of the Russian economy.

The president said the penalties were the result of "choices the Russian government has made, choices that have been rejected by the international community."

The sanctions announced Thursday followed a first round of economic penalties levied earlier in the week on 11 people the U.S. said were involved in the dispute in Ukraine. Russia moved its military into Ukraine's Crimean Peninsula three weeks ago and has since formally annexed the strategically important region into its borders.

The U.S. has declared Russia's incursion into Crimea a violation of international law and does not recognize its annexation of the peninsula.