NEW YORK - Republican vice-presidential nominee Sarah Palin defended her remark that the proximity of Russia to her home state of Alaska gives her foreign policy experience, explaining in a CBS interview airing Thursday that "we have trade missions back and forth."

Palin has never visited Russia and until last year the 44-year-old Alaska governor had never travelled outside North America. She also had never met a foreign leader until her trip this week to New York. In the CBS interview, she did not offer any examples of having been involved in any negotiations with the Russians.

Palin's foreign policy experience came up when she gave her first major interview, on Sept. 11 to ABC News. Asked what insight she had gained from living so close to Russia, she said: "They're our next-door neighbours and you can actually see Russia from land here in Alaska, from an island in Alaska."

The comment met with derision from Palin's critics and was turned into a punch line for a "Saturday Night Live" skit featuring actress Tina Fey. Appearing as Palin, she proclaimed, "I can see Russia from my house!"

In the interview with CBS News anchor Katie Couric, Palin said: "It's funny that a comment like that was, kind of made to ... I don't know, you know? Reporters ..."

Couric said, "Mock?"

"Yeah," Palin said, "mocked, I guess that's the word, yeah."

When Couric asked how Alaska's closeness to Russia enhanced her foreign policy experience, Palin said, "Well, it certainly does because our ... our next-door neighbours are foreign countries." Alaska shares a border with Canada.

Palin didn't answer directly when Couric inquired about whether she had been involved in any negotiations with the Russians.

"We have trade missions back and forth," she replied. As she continued, Palin brought up Russian Prime Minister Vladimir Putin.

"It's very important when you consider even national security issues with Russia as Putin rears his head and comes into the air space of the United States of America, where -- where do they go? It's Alaska. It's just right over the border. It is -- from Alaska that we send those out to make sure that an eye is being kept on this very powerful nation, Russia, because they are right there. They are right next to ... to our state," she said.

Asked why she only obtained a passport last year, Palin said, "I'm not one of those who maybe came from a background of, you know, kids who perhaps graduate college and their parents give them a passport and give them a backpack and say go off and travel the world. No, I've worked all my life. In fact, I usually had two jobs all my life until I had kids. I was not a part of, I guess, that culture."

Earlier Thursday, Palin held a rare exchange with reporters outside a Ground Zero firehouse in New York, and declined to endorse the candidacy of indicted Alaska Senator Ted Stevens. On trial for seven counts of making false statements stemming from allegations that he concealed gifts on Senate financial documents, Stevens is running for re-election to retain the seat he has held since 1968.

When a reporter asked Palin if she supports the re-election of Stevens, she replied: "Ted Stevens' trial started a couple of days ago. We'll see where that goes."

Outside the firehouse just across from the site of the Sept. 11, 2001, terrorist attacks, Palin took just a handful of questions from reporters. She has yet to have a news conference in the four weeks since Republican presidential candidate John McCain chose her to be his running mate and has submitted to only three major interviews: with ABC, Fox News and CBS.

Palin was asked if she thought the U.S. presence in Iraq and Afghanistan was helping to mitigate terrorism.

"I think our presence in Iraq and Afghanistan will lead to further security for our nation. We can never again let them onto our soil," she said.

Wrapping up a trip to New York, the Alaska governor toured a visitors centre dedicated to those who lost their lives in the 2001 attacks. She later walked past a bronze memorial built into the wall of a firehouse, which commemorates the 343 firefighters who died on Sept. 11. She touched the wall several times.

"To come here and see these good New Yorkers who are not only rebuilding this area but rebuilding America, it's very inspiring," she told reporters.

Palin asked several questions during the tour about progress rebuilding the trade centre site, victims' families and particularly the health problems suffered by Ground Zero workers, said Jennifer Adams, CEO of the tribute centre. Health advocates believe thousands of people became ill from exposure to toxic dust from the ruins of the trade centre site.

Palin's parents went to New York in January 2002 to help control the rat population in Staten Island's Fresh Kills landfill as part-time contract workers with the Agriculture Department, her mother, Sally Heath, told The Associated Press on Thursday.

Their task for two weeks was to control the rats so that they did not disturb the debris from the World Trade Center that was being brought there and searched by forensic teams for human remains.