Dan Pfeiffer, a senior adviser to President Barack Obama, said Sunday, “We are putting as much pressure on the Russians as we can to do the right thing” in Ukraine. Voters in the Crimea region of Ukraine, now occupied by troops from Russia, were casting ballots in a referendum Sunday to determine whether Crimea will rejoin Russia. “You can expect sanctions designations in the coming days,” Pfeiffer said on NBC’s Meet the Press, as Obama identifies specific Russians whom the United States will seek to punish with visa bans and asset freezes. Pfeiffer did not directly answer the question of whether Obama would draw a “red line” at eastern Ukraine – outside of the Crimea region – as a line Russian President Vladimir Putin’s forces must not cross. Pfeiffer also sidestepped the question of U.S. military aid for the new government of Ukraine, saying only that “we’re looking at all ways of assistance.” But he urged Congress to pass the economic aid bill which the Senate Foreign Relations Committee approved last week. The Senate bill provides for loan guarantees for Ukraine, in line with the $1 billion announced by the Obama administration. It also directs the administration to help the Kiev government recover assets linked to acts of corruption by deposed Ukrainian president Viktor Yanukovich, members of his family, or other former or current Ukrainian government officials. It spends $150 million for military cooperation, pro-democracy efforts, and clean government in Ukraine. Just back from a brief visit to Ukraine, Senate Majority Whip Dick Durbin, dismissed Sunday’s referendum as “a Soviet-style election -- we know what the ending is going to be” and called the Russian occupation of Crimea “the most single most serious act of aggression since the Cold War.” Also part of the Senate delegation that visited Ukraine, Sen. Jeff Flake, R-Ariz., said that Ukraine’s ability to withstand Russian pressure is limited by that fact that the Ukrainian military “has been hollowed out over the past couple of years. According to some Ukrainians, ‘we have nothing that shoots, runs or flies.’ And it’s because the Russians have had such close ties to the previous (Yanukovich) government that they hollowed the military out. So, yes, they need a lot of help. But nothing that we can do will help Ukraine withstand what Russia is going to do if they decide to go into” other parts of Ukraine beyond Crimea. Flake added that “it’s going to be difficult” to undo the Russian annexation of Crimea. “All you can do is to increase the costs significantly and hope that they don’t move further into Ukraine.” The Kremlin Sunday issued a statement saying that Putin told German Chancellor Angela Merkel in a phone call Sunday that the referendum in Crimea complies with international law. On Saturday Russia vetoed a proposed United Nations Security Council resolution which urged countries not to recognize the results of the Crimea referendum. Thirteen of the Council's 15 members voted in favor of the resolution, while China abstained.