NORFOLK — Bernie Sanders took aim Tuesday at Hillary Clinton for having supported the North American Free Trade Agreement while her husband was president, as the senator from Vermont continued a new push to draw distinctions with his Democratic presidential rival.

Appearing before a boisterous crowd here of about 4,500 people in a hockey arena, Sanders touted his long record of opposition to trade deals and said that as first lady Clinton “thought NAFTA was a good idea” when it was passed in the early 1990s.

“I was right. She was wrong,” Sanders said.

“I understood that American workers should not be forced to compete against desperate people making pennies an hour,” Sanders said. “I want to see poor people around the world do better, but that does not mean we have to destroy the middle class of this country.”

His appearance came in advance of the March 1 primary in Virginia, one of 11 states with Democratic nominating contests on what could be a pivotal day in Sanders’s race with Clinton. Sanders told his crowd, which was skewed young and was racially diverse, that “we think we can win here in Virginia if people come out to vote.”

In the wake of his loss to Clinton in the Nevada caucuses, Sanders announced Monday that he planned to step up his efforts to draw contrasts with Clinton, including on trade. Sanders has previously criticized Clinton for her relatively recent opposition to the Trans-Pacific Partnership, a deal championed by President Obama that Sanders has characterized as “disastrous.”

Clinton was supportive of her husband’s efforts to implement NAFTA, an agreement that she has since said fell short of expectations. Obama, when he faced off against Clinton in the 2008 Democratic primaries, also sparred with Clinton over her support of her husband’s deal.

As Sanders said he was about to discuss what he advertised as an important difference with Clinton, some in the crowd booed in reference to her.

“No, no,” Sanders said. “I respect Secretary Clinton. We can have differences.”