US President Donald Trump has said "it's time" for the US to plough on with tax reform.
Trump made simplifying the tax code and reducing tax rates central to his campaign for the presidency.
However, he has said Congress must come up with the details for the tax proposals, and that lawmakers must present a bill in the next few months.
Powerful business groups such as the Chamber of Commerce and Business Roundtable have backed efforts to reform the tax code.
Speaking in Springfield, Missouri, Trump said: "We're here today to launch our plans to bring back Main Street by reducing the crumbling burden on our companies and on our workers.
"The foundation of our job creation agenda is to fundamentally reform our tax code for the first time in more than 30 years."