US President Barack Obama has unveiled a $450bn (£282bn) package of tax cuts and spending plans aimed at creating jobs and boosting the economy.It includes funding for teachers and firefighters - and tax cuts to small businesses to encourage employment.Mr Obama told a joint session of Congress that politicians needed to act quickly to pass the package.Republican congressman John Boehner, whose support is likely to be crucial, said the plans The Republicans control the House of Representatives, and have managed to derail many of Mr Obama's legislative proposals.Some Republicans have already dismissed the plan as a crude attempt to boost the president's flagging popularity in the run-up to next year's presidential election.Some 9.1% of Americans are currently out of work, and the issue is expected to dominate the election campaign.The BBC's North America editor Mark Mardell says the president has set a trap for the Republicans - either they back his proposals, or he will campaign against what he will portray as a Washington elite happy to cut taxes for their rich friends but not for ordinary people.In his speech, Mr Obama urged Congress to "stop the political circus" and said everything in the jobs plan was based on principles already supported by Republicans and Democrats."The purpose of the American Jobs Act is simple: to put more people back to work and more money in the pockets of those who are working," he said."It will create more jobs for construction workers, more jobs for teachers, more jobs for veterans, and more jobs for the long-term unemployed."The president has yet to give details on how the plans would be paid for, but he hinted that the money could be found in spending cuts and promised to release more details on 19 September.The centrepiece of the proposal is to expand a cut in the Federal Insurance Contributions tax, a levy paid by employers and workers to fund social security and healthcare for retirees.Congress approved a cut in the tax for workers last year, from 6.2% to 4.2%. But that measure was due to expire in December.Mr Obama wants to continue that cut next year, lower the tax even further to 3.1% for workers, and extend a similar cut to companies, at a cost of $240bn.He also proposed providing $85bn in federal government aid to local and state governments, to be spent among other things on helping to keep teachers and emergency services workers in jobs.And a further $50bn should be spent on infrastructure projects, including a plan to upgrade the country's airports, he said.The president wants to submit the bill to Congress next week.Mr Boehner, the Republican speaker of the House of Representatives, said he hoped that Democrats and Republicans could work together on the bill."The proposals the president outlined tonight merit consideration. We hope he gives serious consideration to our ideas as well," said Mr Boehner.Some Republicans have said they would support at least part of the plan, but others have already indicated their opposition.Representative Paul Broun of Georgia, one of the Republicans who chose not to attend the speech, tweeted: "This is obviously political grandstanding and class warfare."The two parties clashed all summer over plans to sort out the country's debt levels, which prompted a historic US government credit downgrade.The political battles on Capitol Hill have seen the president's approval slump, but ratings for Congress have been even lower.