WASHINGTON, Rajab 3, 1435, May 2, 2014, SPA -- U.S. President Barack Obama and German Chancellor Angela Merkel warned Russia on Friday it will face additional sanctions against key sectors of its economy if Moscow disrupts Ukraine's plan to hold elections on May 25, Reuters reported. The two leaders linked the threat to the election when they addressed a joint news conference in the White House Rose Garden after Oval Office talks dominated by the situation in Ukraine. Obama and Merkel said they were united in vowing to move to the tougher sanctions but did not say specifically which sectors of the Russian economy would be targeted. The election is to choose a successor to President Viktor Yanukovitch, the pro-Russian leader who resigned in the face of unrelenting protests and whose ouster has provoked the worst East-West crisis since the Cold War. In recent weeks pro-Russian separatists have stirred turmoil in eastern Ukraine in what the West sees as an attempt by Russian President Vladimir Putin to invite Russian intervention, much as occurred in Moscow's seizure of Crimea in March. U.S. officials said a next round of sanctions could affect vital parts of the Russian economy such as energy, defense, financial services and engineering. "If, in fact, we see the disruptions and the destabilization 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," Obama said. The United States and European allies have been carefully watching the movements of 40,000 Russian troops massed on Ukraine's eastern border and the takeover of buildings in cities in eastern Ukraine by armed pro-Russian militants. They have warned that an outright invasion would trigger broad, damaging economic sanctions. -- SPA 22:27 LOCAL TIME 19:27 GMT www.spa.gov.sa/1227966