RICHMOND, Virginia (Reuters) - Democrat Barack Obama said on Wednesday the United States must be vigilant against attack during the transition to a new president, no matter whether he or Republican rival John McCain wins the November 4 White House race.

With less than two weeks until the election, McCain focused on the economy, the No. 1 issue for most voters, and criticized Obama for having “skewed” economic priorities.

Both candidates welcomed a White House announcement that the United States will host an international summit to talk about global economic turmoil beginning on November 15.

Although the economy has been driving the campaign, Obama took time out to rebut McCain’s criticism of Democratic vice presidential candidate Joe Biden for predicting an Obama administration would face a major international challenge as a test within six months of taking office.

At a news conference in which he admitted “Joe sometimes engages in rhetorical flourishes,” Obama cautioned that whoever replaces President George W. Bush will face threats and tests, in part because of Bush’s “bad set of policies” that resulted in two unresolved wars and an “economy in free fall.”

“A period of transition to a new administration is always one in which we have to be vigilant,” Obama said. “We have to be careful, we have to be mindful that as we pass the baton in this democracy, that others don’t take advantage of it. That is true whether it’s myself or Senator McCain.”

But McCain’s campaign, which repeatedly has blasted the 47-year-old Obama as being unready to be president, rejected the explanation.

“Joe Biden guaranteed a generated international crisis if Barack Obama is elected, and a smile-for-the-cameras press conference isn’t going to mitigate the risk of an Obama presidency,” said McCain spokesman Tucker Bounds.

MCCAIN TALKS TAXES, OBAMA EXPANDS LEAD

The foray into foreign policy was a change from Obama’s emphasis on the economy, an issue that has helped him move ahead in the polls. In a Reuters/C-SPAN/Zogby poll released on Wednesday Obama expanded his lead over McCain to 10 points.

At a campaign event in New Hampshire, McCain hammered Obama’s tax plan as simply a way to redistribute wealth.

“Before government can redistribute wealth, it has to confiscate wealth from those who earned it,” he said. “Whatever the right word is for that way of thinking, the redistribution of wealth is the last thing America needs right now.”

“What are really skewed in all of this are my opponent’s priorities. He talks about our economy in a detached and academic way, forgetting that the goal is not to redistribute wealth but to create it,” he said to applause.

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Obama defended his plan for a middle class tax cut.

“The difference is, he wants to give a $700,000 tax cut to the average Fortune 500 CEO. I want to put a middle class tax cut in the pockets of 95% of workers and their families,” Obama said at a rally in Richmond.

“My opponent doesn’t want you to know this, but under my plan, tax rates will actually be less than they were under Ronald Reagan,” Obama added.

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Where the candidates were campaigning said a lot about the state of the race late into the campaign.

With less than two weeks to go, Obama was in Virginia with a chance to win that state for a Democrat for the first time since 1964 and McCain was in a New Hampshire, a small state but one the Republicans need as the number of winnable alternatives dwindles.

The Republican later joined his running mate, Alaska Gov. Sarah Palin, for a joint rally in Ohio, a hotly contested state.

Palin referred to Obama as “Barack-the-wealth-spreader” and said he was not being candid about his tax plans.

“We want to keep more American money in America,” she told a crowd of thousands in Green, Ohio, repeating McCain’s promises to cut the capital gains tax and business tax rates.

Though McCain needled Obama for being overconfident, Obama warned supporters who packed a hockey arena to see him against premature celebration.

“I need you to make it happen,” he told the chanting crowd of more than 12,000. “I ask you to knock on some doors, make some calls, talk to your neighbors, and give me your vote.”