WASHINGTON (Reuters) - U.S. Senate Democrats on Wednesday narrowly blocked legislation that would slow the entry of refugees from Syria and Iraq to the United States in a contentious vote cloaked in presidential election-year politics. The vote was 55-43, with “yes” votes falling short of the 60 needed to advance the Republican-backed measure in the 100-member Senate. No Republicans voted against the bill, and only two Democrats backed it. Among other things, the bill would halt the admission of refugees and require high-level U.S. officials to verify that each refugee from Iraq and Syria posed no security risk before being allowed into the United States. Republicans said the tighter screening was essential to ensure the safety of Americans and prevent attacks within the country by Islamic State and other militant groups. “This bipartisan bill would allow Washington to step back, take a breath and ensure it has the correct policies and security screenings in place,” Republican Majority Leader Mitch McConnell said in the Senate before the vote. Democrats called the legislation an attack on people who  are fleeing war. They accused Republicans of holding the vote to allow their 2016 presidential candidates serving in the Senate to back legislation touted as tough on security. All three Senate Republican 2016 presidential hopefuls, Ted Cruz, Rand Paul and Marco Rubio, backed the bill. Democratic presidential candidate Bernie Sanders missed the vote. Democrats also sought to play politics. They tried and failed to reach a deal with Republicans to set up a vote on an amendment establishing a religious test for would-be immigrants. That vote was planned to see if Republicans would side against presidential candidate Donald Trump, who has advocated barring Muslims from entering the United States.   The Syria refugee bill passed the House by a large margin days after the Nov. 13 Islamic State attacks in Paris. The bill was supported by dozens of Democrats who defied Democratic President Barack Obama’s veto threat. “We need to talk about efforts to defeat ISIS, not creating more paperwork for cabinet secretaries,” Harry Reid, the Senate Democratic leader, told reporters before the vote. It currently takes 18-24 months for Syrian refugees to be screened before they can move to the United States. Washington has offered refuge to far fewer of the millions fleeing war in Syria and Iraq than many of its closest allies in Europe and the Middle East. Obama announced last year that he would admit 10,000 Syrians. 