U.S. President Barack Obama is back to campaigning for reelection after spending most of the week heading Washington's response to Superstorm Sandy.

The incumbent Democrat was in Wisconsin, Nevada and Colorado Thursday — three so-called “battleground states” that could determine whether he or Republican Mitt Romney wins next Tuesday's presidential election.

Mr. Romney was in Virginia, another crucial state in the November 6 election.

Both men criticized each other's plans for improving the sluggish U.S. economy. Mr. Romney told supporters in Roanoke that middle income Americans have been “squeezed” financially during Mr. Obama's first term in office. He says incomes have dropped while necessities such as gasoline and health insurance have gone up.

Mr. Obama told supporters in Las Vegas, Nevada that Mr. Romney touts economic policies favoring the wealthy — policies he says failed in the past. The president chided his Republican rival for dressing up these old policies as “change.”

Also Thursday, New York City Mayor Michael Bloomberg endorsed Mr. Obama for a second term. The mayor, a former Republican turned Independent, cited the president's efforts to fight pollution from cars and factories. Many scientists say carbon emissions contribute to global warming and possibly more powerful storms like Sandy.

President Obama says he is honored to have the mayor's endorsement. The president says although they do not agree on every issue, they both back improvements in education, immigration reform, and fighting climate change.

Bloomberg is mayor of the United States' largest city and is a major endorsement. New York was devastated by this week's storm.

With less than a week before Election Day, polls show the race is tied.

OPTIONAL ROMNEY SOUNDBITE:

“The median income in America has dropped by $4,300 over the last four years. So now, you're earning 43 hundred dollars a year less than you were four years ago. And gasoline prices, they've gone up $2,000 per family. And health insurance costs, they've gone up $2,500 a family.”

OPTIONAL OBAMA SOUNDBITE:

“And what the governor's offering sure ain't change. Giving more power back to the biggest banks isn't change. Leaving millions without health insurance isn't change. Another $5 trillion tax cut that favors the wealthy isn't change. Refusing to answer questions about the details of your policies isn't change.”