MIAMI (AP) — Hillary Clinton widened her lead over Democratic rival Bernie Sanders as black voters helped her secure key victories in Alabama, Arkansas, Georgia, Tennessee and Virginia in the Super Tuesday contests.

Sanders won his home state of Vermont and pledged to stay in the race.

Clinton aims for a sweep of Southern states in the delegate-heavy series of primaries and caucuses Tuesday. Sanders could bank only on the home-state win and both campaigns were vying for support in Colorado, Massachusetts, Minnesota and Oklahoma.

As polls closed, Clinton spoke to a forum of black women hosted by the television network BET at the St. Regis hotel in Miami.

"I'm thinking about how we can elevate the political dialogue away from the insults and really mean-spirited language," she said.

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Clinton and her allies have already shifted some attention to Donald Trump, casting the Republican front-runner as divisive and unprepared to lead the country. The Republican contest, said Clinton, has "turned into a kind of one-upsmanship on insulting."

All told, Clinton and Sanders were competing for 865 delegates in 11 states and American Samoa on Tuesday, the biggest single-day prize of the 2016 campaign.

Clinton is now assured of winning at least 175 delegates on Tuesday. Sanders will receive at least 71.

According to the AP's count, Clinton now has at least 723 delegates, including super delegates — the party leaders and members of Congress who can support any candidate. Sanders has received at least 158. It takes 2,383 delegates to win the nomination.

Black voters powered Clinton to victory in South Carolina last weekend and were expected to give her a huge advantage throughout the South.

Nearly half of Democratic primary voters in Alabama and Georgia were black, according to early results of exit polls conducted for The Associated Press and television networks. In Texas, about 3 in 10 Democratic primary voters were Hispanic and a little fewer than 2 in 10 were black.

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Greta Lewis voted with her mother at the Central Christian Church in Memphis. Both women are black and chose Clinton.

"She has been the one who has stepped out to at least try to identify with most of the minorities, whether they're women, black, Asian, Hispanic," said Lewis, a 31-year-old receptionist at her mother's dental office.

Exit polling also showed voters pushing to continue President Barack Obama's policies rather than the kind of leftward shift championed by Sanders.

Clinton visited Minnesota before heading to Miami, foreshadowing the importance of Florida for the general election.

Sanders decamped to his home in Burlington, Vermont. He has vowed to stay in the race until the party's convention — and he showed no signs of retreating as he addressed a raucous rally of supporters after the Vermont polls closed.

"Thirty-five states remain and let me assure you that we are going to take our fight for economic justice, for social justice, for environmental sanity, for a world of peace, to every one of those states." Sanders said.

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The event had the feel of a valedictory for Sanders, who said he was "so proud to bring Vermont values all across this country."

Despite his obstacles, the Vermont senator has little incentive to fold. He reported raising more than $42 million in February, a sign that he will have the money to go deep into the spring.

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Thomas reported from Essex Junction, Vermont. Associated Press writer Josh Boak in Washington contributed to this report.