MIAMI -- President Barack Obama walked into the mouth of a giant tunnel in Miami on Friday to highlight proposals to boost investment in U.S. infrastructure, a move designed to show a leader still focused on the economy in the midst of broader policy battles in Washington.

Obama's tour of the Port of Miami tunnel project and a subsequent speech were aimed at convincing members of the U.S. Congress to back proposals that would siphon billions in taxpayer dollars into public road, bridge and other infrastructure projects.

"My main message is, let's get this done," he said. "Let's rebuild this country that we love."

Obama, as he has in the past, said he wanted to develop a national infrastructure bank and capitalize it with $10 billion.

He would also create "America Fast Forward Bonds" that would help state and local governments attract money for infrastructure projects. These would be direct subsidy bonds in which the issuer would receive a 28 percent subsidy of the borrowing cost as a way of attracting a wider set of investors.

In addition, Obama would add $4 billion to support two programs that are used to provide grants for infrastructure projects like the Miami tunnel.

Alan Krueger, Obama's chief economist, told reporters traveling with the president on Air Force One that the three main proposals outlined by Obama would cost some $21 billion.

Obama's fiscal 2014 budget proposal, which will be released on April 10, would spell out how they are paid for, he said. All of the proposals require congressional approval.

It is unclear how far the proposals will go in Congress. Republicans are reluctant to support what they consider government stimulus spending after a much criticized $787 billion stimulus plan that Obama managed to push through Congress in 2009.

Florida's Republican governor, Rick Scott, said his state has been able to improve the Florida economy without Washington's assistance.

"In Florida, we've managed to grow jobs by cutting taxes, paying down debt and balancing the budget - a stark contrast to the ways of Washington," he said.

Obama noted that some people on both sides of the political spectrum, such as labor unions and the Chamber of Commerce, had supported his infrastructure ideas.

"Building bridges and schools, that's not a partisan idea," he said.

Obama was criticized in his first term for focusing too much on his signature policy goal of revamping the U.S. healthcare system, which critics said resulted in him giving less attention to the slow economic recovery.

The White House rejects that charge.

Since his re-election in November and his January inauguration, Obama has steered a policy push focused primarily on passing both immigration reform and tighter gun control measures.

However, his State of the Union address in February included a series of measures to boost the economy, and the Florida trip fleshed out some of those ideas.

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