U.S. President Barack Obama has told supporters in the “battleground state” of Colorado that Americans unify during times of crisis, referencing the onslaught of Hurricane Sandy earlier this week and wildfires and a mass shooting that took place in Colorado earlier this year.

Having resumed campaigning after several days off to deal with storm recovery, Mr. Obama said Thursday in boulder that America rises or falls as “one nation, one people.”

He also said he is not afraid to make unpopular choices, such as the government bailout for the auto industry during the early months of his presidency.

Mr. Obama's Republican rival, former Massachusetts governor Mitt Romney, campained in Virginia Thursday, another crucial state in the November 6 election.

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.

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.