President Obama on Wednesday called on Congress to act swiftly to approve billions of dollars in funding for the nation’s aging roads, bridges and rail systems, warning that a failure to do so may cost the economy 700,000 jobs.

Speaking on the banks of the Hudson River, Obama said no sector suffered more in the recession than the construction industry, arguing that new public works projects would help put many back to work and attract businesses deciding whether to locate in the United States or overseas.

“Building a world-class transportation system is one of the reasons America became an economic superpower in the first place,” Obama said, noting the decline in federal investment in recent years as China and other developing countries increase their spending. “First-class infrastructure attracts first-class jobs.”

The event was held at the Washington Irving Boat Club in the shadow of the Tappan Zee Bridge, its trademark traffic crawling across the span over the Hudson north of Manhattan. The venue was chosen to highlight a federal loan program that helps states replace aging roads and bridges, such as the Tappan Zee, now nearly six decades old and carrying far more traffic than intended.

Obama’s remarks are the most public in a series of appearances that senior administration officials are making this week to highlight the need for new spending on languishing projects for highways, airports and more. Obama again argued that improving transportation services is a key to short-term job growth and long-term economic success. He was joined by New York Gov. Andrew M. Cuomo (D), who thanked the administration for the $1.6 billion federal loan that is helping to finance the construction of the replacement for the Tappan Zee Bridge.

“This is a bridge from gridlock to bipartisanship, this is a bridge from paralysis to progress, and this is a bridge from yesterday to tomorrow,” Cuomo said as cranes being used to raise the new bridge across the Hudson idled behind him on a breezy day.

As the midterm elections approach, Democrats hope to use the issue of transportation funding to highlight Republican recalcitrance in Congress. In New York, Obama also announced a series of bureaucratic steps to better coordinate the federal permitting process, hoping to speed the time it takes to get transportation projects approved for construction.

Administration officials say Republicans and Democrats have largely agreed about spending on transportation services in the past, given the value such government projects have to the private-sector economy. But administration officials say that unless Congress approves new spending soon, the federal Highway Trust Fund will run out of money this summer.

“If they don’t act by the end of the summer, federal funding for transportation projects will run out,” Obama said of Congress, placing the preponderance of blame on Republicans. “Instead of putting more workers back on the job,” Obama said, “they are putting those jobs at risk.”

The administration says that the fund’s bankruptcy would delay more than 100,000 road projects and more than 5,000 transit projects and jeopardize 700,000 construction jobs. During his speech, Obama said that number was roughly the population of Tampa.

Michael Steel, a spokesman for House Speaker John A. Boehner (R-Ohio), questioned Obama’s commitment to public works spending and job creation and cited the administration’s more-than-five-year deliberation over whether to build an oil pipeline from Canada to Nebraska for eventual delivery to the Gulf Coast. “An infrastructure for the 21st century is going to require energy, and plenty of it,” Steel said. “So why is the White House blocking the Keystone pipeline and the tens of thousands of American jobs it would create?”

The White House sent the Grow America Act, a broad transportation measure that includes guidelines for allowing new toll highways, to Congress this spring. A bipartisan group of senators is working on its own long-term transportation plan.

Transportation Secretary Anthony Foxx, who accompanied Obama to New York, told reporters this week that short-term spending measures — the divided Congress’s preferred way to fund the government in recent years — have put off the planning and financing of long-range projects essential to solving, rather than just managing, the nation’s growing transportation problems.

Those include bridges coming to the end of their planned use, including the Tappan Zee, and overburdened airports, rail systems and roads.

By 2050, Foxx said, the country’s transportation system will need to move 100 million more people and 14 billion additional tons of freight, nearly twice the current level. The administration, drawing on calculations made by the American Society of Civil Engineers, estimates that $3.6 trillion in spending will be needed to sufficiently address the mounting infrastructure problems by the end of the decade.

Foxx said the Senate, controlled by Democrats, has shown support for the measure. But the Republican-led House poses a larger challenge, and Foxx said the administration has much work to do if the measure is to succeed. “I have spent a lot of time and a lot of shoe leather on both ends of Capitol Hill, and what I can tell you is, is that people on both sides of the aisle want to see something get done,” he said. “But we’re going to have to work at it, and this is going to be a nine-inning game. It’s not going to get solved in the first inning.”

As Obama visited the iconic New York bridge, Vice President Biden traveled to Cleveland to make a similar push for transportation spending.

While in New York, Obama will do some fundraising for the Democratic Party in Manhattan, and Thursday, he will mark the ceremonial opening of the National Sept. 11 Memorial and Museum in Lower Manhattan.