On the eve of his debut on the international stage, Mitt Romney sat down for a television network interview here on Wednesday and answered questions about a host of issues, including the mass killing last week in a Colorado movie theater.

Embarking on a week-long foreign trip, Romney reiterated his opposition to stricter U.S. gun laws in response to the ranpage, allegedly by a failed graduate student, that left 12 dead and 58 injured.

“I don’t happen to believe that America needs new gun laws. A lot of what this young man did was clearly against the law, but the fact that it was against the law did not prevent it from happening,” Romney told “NBC Nightly News” anchor Brian Williams in an interview taped outside the Tower of London.

Romney acknowledged that as governor of Massachusetts he supported a bill that banned assault weapons, but he said he opposes a similar measure for the rest of the country.

“We can sometimes hope that just changing a law will make all bad things go away. It won’t. Changing the heart of the American people may well be what’s essential to improve the lots of the American people,” he said.

Romney is scheduled to meet Thursday with top British officials, including Prime Minister David Cameron and former prime minister Tony Blair.

Romney will attend Friday’s Summer Games Opening Ceremonies — although he told Williams he will not have a chance to see his wife Ann’s horse, Rafalca, compete in the dressage events — and later visit Israel and Poland.

On Tuesday in Reno, Nev., Romney delivered a forceful and at times scathing critique of President Obama’s foreign policy. Romney pledged to refrain from such rhetoric during his overseas trip.

When he landed here Wednesday, Romney was greeted by a report in the London Telegraph that an unnamed “adviser” to his campaign said the Republican candidate has a better appreciation than Obama for America’s “Anglo-Saxon heritage.”

Romney campaign aides quickly dismissed the report as not true. Vice President Biden weighed in with a statement saying, “This assertion is beneath a presidential campaign.”

Asked by Williams about the quote, Romney said he has “a lot of advisers.”

“I’m not sure who this person is,” Romney said, “but I can tell you that we have a very special relationship between the United States and Great Britain. It goes back to our very beginnings — cultural and historical. But I also believe the president understands that.”

Williams noted that many Americans do not yet feel that they know Romney, and the candidate said he sees the fall debates as a chance for people to understand his character.

When Williams asked Romney if he was “a hidden man,” Romney said, “I’m happy to talk about my heritage.”

He said his father, George, was born in Mexico and added that he is “proud” of his Mormon faith, which Romney rarely talks about on the campaign trail.

“Without question, I’m a member of the Church of Jesus Christ of Latter-day Saints,” Romney said. “I’m proud of that. Some call that the Mormon Church; that’s fine with me. I’ll talk about my experiences in the church. There’s no question they’ve helped shape my perspective.”

With the Republican National Convention in Tampa a month away, Romney said he has not yet made a decision about a vice presidential running mate and that he would not make his announcement while traveling overseas.

When Williams asked Romney whether he could confirm that he is seeking an “incredibly boring white guy” for his vice presidential candidate, Romney laughed and quipped, “You told me you were not available.”