LAS VEGAS — Thousands of people rallied Saturday in several cities in a bid to urge Congress to act swiftly on immigration reform. Outside a federal building in Las Vegas, demonstrators cheered Senate Majority Leader Harry Reid and Rep. Shelley Berkley, D-Nev., who told them they’re committed to making immigration reform a top priority. In the crowd, activists waved American flags while others held signs with slogans such as “Stop Tearing Our Families Apart,” ”Reform Now” and “Workers, Taxpayers, Voters.” Reid, fresh from the recent health care reform fight and facing a tough re-election campaign of his own, told the crowd that there’s urgency to pass immigration reform legislation, which would include border security and a guest worker program for seasonal workers. Demonstrators also cheered Rep. Luis Gutierrez, D-Ill., who has introduced immigration reform legislation that includes the path to legal status for millions of illegal immigrants. “We’re looking forward to the bill being introduced in the Senate and to Sen. Reid to help push it through the Senate,” said Shu Ohno of the Reform Immigration for America Campaign. “We believe immigration reform is a necessary component of economic recovery.” Police estimated the crowd at the three-hour rally at roughly 3,500, while organizers said put the figure at 10,000. In Seattle, thousands gathered at Occidental Park, where U.S. Sens. Maria Cantwell and Patty Murray addressed the crowd by video and Seattle Mayor Mike McGinn was speaking in person. In Chicago, more than 1,000 activists attended a rally on the city’s West Side calling for reform. Lawmakers failed to agree in 2006 and 2007 when they last tried to overhaul the immigration system. Last month, tens of thousands of demonstrators rallied and marched through the streets of Washington in an effort to prod congressional action on immigration reform.