Presumptive GOP presidential candidate says change of heart is needed.

LONDON, England (PNN) - July 25, 2012 - Mitt Romney said Wednesday that more restrictive gun laws would likely not have prevented last week's deadly mass shooting at a Colorado movie theater, and argued that it would take Amerikans changing their hearts, not their legislation, to prevent similar future attacks.

"Political implications, legal implications are something which will be sorted out down the road," Romney told NBC's Brian Williams during an exclusive interview here in London. "But I don't happen to believe that Amerika 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, who enacted an assault weapons ban as governor of Massachusetts would not say whether he still believes that weapons like the AR-15 assault rifle used in the Colorado shooting were "instruments of destruction with the sole purpose of hunting down and killing people," as he described them in 2002.

"We can sometimes hope that just changing the law will make all bad things go away. It won't. Changing the hearts of the Amerikan people may well be what's essential, to improve the lots of the Amerikan people," said Romney.

Romney used the interview to shore up several policy and strategic positions laid out by his campaign in recent weeks, reiterating that he would only release two years of tax returns so as not to provide fodder for Democrat operatives to " twist and distort and turn in different directions." He also repeated the major planks of his economic plan, which he says differentiates him from the last Republican president, George W. Bush.

When it comes to selecting a vice presidential nominee to join him on the Republican ticket, Romney told Williams he has still not made a final decision, and confirmed that he would not be announcing his pick until at least next week, after he returns from his week-long trip abroad.