Former Massachusetts governor Mitt Romney is neck-and-neck with President Obama among registered voters in three key swing states, a new NBC News/Marist poll finds.

In Iowa, including leaners, Obama and Romney, the presumptive Republican nominee, are tied at 44 percent. In Colorado, Obama takes 46 percent and Romney 45 percent. In Nevada, Obama is at 48 percent to Romney’s 46 percent.

Obama won all three of these states in 2008, but President George W. Bush took them all in 2004. These surveys suggest Obama will have to fight to keep all three in his column.

“These are very, very competitive states,” said Marist polling director Lee Miringoff in a statement. “Everything is close.”

Responses to questions about the economy are mixed, but overall the results favor Romney.

Majorities in each state say the country is on the wrong track, a clear warning for President Obama. That’s despite the fact that majorities in all three think the worst economic pain is behind us.

On the critical question of who would better handle the economy, Romney leads Obama by three points in Colorado and five points in Iowa. In Nevada, the two candidates are tied.

Last week Marist found Obama had a slight lead in three other swing states — Florida, Ohio and Virginia.

The poll also shows Sen. Dean Heller (R) and Rep. Shelley Berkley (D) deadlocked in the Senate race in Nevada at 46 to 44 percent.

The poll was conducted May 22 to 24 by landline and cellphone, with a little over 1,000 voters in each state. The head-to-head results in all three states are within the survey’s 3 percent margin of error.