Questions are being raised about expenses Republican vice-presidential candidate Sarah Palin charged as governor. At the same time, Democratic vice-presidential candidate Joe Biden drew criticism for saying Barack Obama will face a "generated crisis" soon after he's elected.

Palin reportedly charged $20,000 to her state to have her children travel with her, including events where they were not invited, according to an Associated Press investigation.

The expenses included costs for hotel and commercial flights for three daughters to join Palin to watch their father in a snowmobile race. She later amended expense reports to specify that they were on official business, the Associated Press reported.

Although Alaska law does not specifically address expenses for a governor's children, Palin has portrayed herself as a frugal politician.

For example, during her campaign for governor she had criticized her opponent, then governor Frank Murkowski, for his use of a private jet. She sold the plane soon after winning the election.

World to 'test the mettle' of Obama, says Biden

Meanwhile, Palin and John McCain are pounding away at Biden over comments he made this weekend in which he said Obama would face a generated crisis as soon as he took office.

"Mark my words. It will not be six months before the world tests Barack Obama like they did John Kennedy. The world is looking," Biden said. "Watch, we're gonna have an international crisis, a generated crisis, to test the mettle of this guy."

In a rally Tuesday in Harrisburg, Penn., McCain pounced on Biden's statement.

"We don't want a president who invites testing from the world at a time when our economy is in crisis and Americans are already fighting in two wars," he said.

In an interview with CNN, Palin accused the media of giving Biden a pass on his remarks.

"Can you imagine if I would've said such a thing?" Palin said.

"Why would you say that, mark my words, this nation will undergo international crisis if you elect Barack Obama? If I would've said that you guys [would have] clobbered me."

With the Nov. 4 general election fast approaching, polls suggest Obama has a solid lead against McCain. While some polls had shown the race tightening, according to a Reuters/C-SPAN/ Zogby poll and an NBC News/Wall Street Journal poll just released, Obama has a 10-point lead over McCain.

With files from the Associated Press