ROUGH CUT (NO REPORTER NARRATION)<br/> <br />U.S. President Barack Obama on Friday (May 2) called on Russia to influence pro-Russian military groups in Ukraine to stand down and said it was disgraceful that the militias were holding international observers.<br/> <br />Obama, speaking at the White House with German Chancellor Angela Merkel, said they were united in their desire to impose costs on Russia for its actions in Ukraine.<br/> <br />"If in fact we see the disruptions and the destabilizations continuing so severely that it impedes elections on May 25th, we will not have a choice but to move forward with additional, more severe sanctions," said Obama.<br/> <br />German Chancellor Angela Merkel said on Friday "we are ready and prepared" to impose sectorial sanctions on Russia.<br/> <br />"This is something that we don't want. We have made a diplomatic offer... so it's very much up to the Russians which road we will embark on," said Merkel.<br/> <br />Merkel, appearing at the White House with President Barack O
