The U.S. State Department imposed a visa ban for those involved in threatening the territorial integrity of Ukraine, the Obama administration said Thursday. President Obama also signed an executive order authorizing sanctions on individuals and entities responsible for activities undermining democratic processes or institutions in Ukraine, including "purporting to assert governmental authority over any part of Ukraine without authorization from the Ukrainian government in Kiev," the White House said. The order didn't specify country of origin for the individuals or entities. The Obama administration said it will deny visas to people responsible for "threatening the sovereignty and territorial integrity of Ukraine," responding to Russia after its actions in the pro-Moscow Crimean peninsula after the ouster of Ukrainian President Viktor Yanukovych. A statement issued by the White House press secretary's office said the administration was still reviewing options to respond to "Russia's ongoing violation of Ukraine's sovereignty and territorial integrity," which the White House said constitutes "a threat to peace and security and a breach of international law, including Russia's obligations under the U.N. Charter and of its 1997 military basing agreement with Ukraine, and that are inconsistent with the 1994 Budapest Memorandum and the Helsinki Final Act." The White House said the executive order was flexible enough to target those most directly involved in destabilizing Ukraine and allows for further steps should the situation deteriorate. Already the United States has suspended trade talks and U.S.-Russia military-to-military activities and put on hold participation in preparing for the Group of Eight summit in Sochi, Russia, in June. "Depending on how the situation develops, the United States is prepared to consider additional steps and sanctions as necessary," the statement said.