WASHINGTON, July 24 (Reuters) - Republican presidential

candidate Donald Trump on Wednesday attacked his new Democratic

rival Kamala Harris as the "ultra-liberal driving force" who

should be held responsible for the Biden administration's

policies on immigration.

"As border czar, Kamala threw open our borders that allowed

20 million illegal aliens to stampede into our country from all

over the world," Trump said at a North Carolina rally, his first

since President Joe Biden bowed out of the race at the weekend.

Biden put Harris in charge of working with countries in

Central America to help stem the tide of migration, but she was

not given responsibility for border security nor was she named

"border czar."

To the roars of the crowd, the former president described

Vice President Harris as the most liberal politician ever

elected in American history.

"She will destroy our country if she ever gets elected," the

former president said at the event, held in Charlotte, North

Carolina, one of a handful of battleground states considered

crucial to winning the Nov. 5 presidential election.

Harris, the first Black woman and Asian American to serve as

vice president, would become the first woman elected president

if she prevails on Nov. 5. In the three days since Biden dropped

out, she has shaken up a staid race and sparked new energy among

Democrats.

Trump's rally began two hours before Biden, 81, addresses

the nation from the Oval Office to explain why he dropped out of

the race under mounting pressure from fellow Democrats.

His decision followed a disastrous June debate with Trump

that exacerbated questions about his ability to win the

election, or to serve another four years if he succeeded.

"I have decided the best way forward is to pass the torch to

a new generation. That is the best way to unite our nation,"

Biden will say, according to excerpts of his planned address

released by the White House.

Biden plans to say that he intends to focus on his work as

president in the six months left in his term.

"That means I will continue to lower costs for hard-working

families and grow our economy. I will keep defending our

personal freedoms and our civil rights - from the right to vote

- to the right to choose," according to his prepared remarks,

outlining some themes that Harris is expected to build her

campaign around.

The president returned to Washington on Tuesday afternoon

after isolating with COVID at his home in Delaware, where he

made the announcement that he was ending his campaign.

Earlier on Wednesday, the 59-year-old vice president called

on a rally of more than 6,000 Black women in Indianapolis to

help her revitalize the Democratic campaign.

The Democratic National Committee's rules committee agreed

on Wednesday on a plan to formally nominate Harris as soon as

Aug. 1 -- before the party's Aug. 19-22 convention in Chicago --

with Harris picking a running mate by Aug. 7.

Harris spoke at an event in Indianapolis hosted by the Zeta

Phi Beta Sorority, which was founded at Howard University, the

historically Black college she attended. She hopes to tap

sororities' multi-generational network of Black women -- who

played an important role in Biden's 2020 victory -- to deliver

strong voter turnout for Democrats again in November.

"I thank you. And now, in this moment, our nation needs your

leadership once again," Harris said.

Harris and Trump are closely competitive, public opinion

polls showed this week.

A Reuters/Ipsos poll completed on Tuesday showed Harris with

a marginal two-percentage-point lead over Trump, 44% to 42%. A

CNN poll conducted by SSRS showed Trump leading Harris, 49% to

46%. Both findings were within the polls' margins of error.

BIDEN TO SPEAK

Trump, coming off a triumphant week in which his party

unified around his presidential bid after a failed assassination

attempt two weekends ago, has had to watch as Biden's sudden

departure from the race shifted the narrative and sparked a

surge of attention toward Harris at his expense.

Hillary Clinton, the 2016 Democratic nominee who lost to

Trump, said in an opinion piece in the New York Times ( NYT ), that she

was excited about the Harris candidacy.

"She represents a fresh start for American politics. She

can offer a hopeful, unifying vision. She is talented,

experienced and ready to be president. And I know she can defeat

Donald Trump," Clinton said.

Harris campaign chair Jen O'Malley Dillon said in a memo

made public on Wednesday that Democrats would aim to compete in

the swing states of Michigan, Wisconsin, Pennsylvania, North

Carolina, Georgia, Arizona and Nevada, opening up a map that in

the final weeks of Biden's campaign had appeared to be more

focused on the Midwest.

"This race is more fluid now - the vice president is

well-known but less well-known than both Trump and President

Biden, particularly among Dem-leaning constituencies," O'Malley

Dillon wrote.

The Harris campaign on Wednesday said it has raised $126

million since Sunday, with 64% of donors making their first

contribution of the 2024 campaign.