WASHINGTON (AP) — Seeking to intensify pressure on Russia, President Barack Obama on Thursday expanded U.S. economic sanctions against Moscow over its actions in Ukraine, targeting President Vladimir Putin’s chief of staff and 19 other individuals as well as a Russian bank that provides them support.

Obama, warning of more costs to come for the Kremlin if the situation worsens, said he also had signed an executive order that would allow the U.S. to penalize key sectors of the Russian economy, including its huge energy business. Officials said Obama could act on that authority if Russian forces press into other areas of Ukraine, an escalation of the crisis in Crimea.