By Tim Reid and Harriet McLeod
LOS ANGELES/CHARLESTON, S.C. (Reuters) - Democratic presidential front-runner Joe Biden on Wednesday accused Republican President Donald Trump of fueling the white supremacy blamed for several U.S. mass shootings, as Trump prepared to visit two cities hit by massacres last weekend.
"In both clear language and in code, this president has fanned the flames of white supremacy in this nation," former Vice President Biden was expected to say in a speech in Burlington, Iowa, on Wednesday, according to excerpts released in advance.
One of his rivals for the Democratic presidential nomination, U.S. Senator Cory Booker, was planning to give his own speech on white nationalism and gun violence at the historically black South Carolina church where white supremacist Dylann Roof shot and killed nine people in 2015.
"These acts of hatred do not happen in a vacuum," Booker was expected to say at Emanuel African Methodist Episcopal Church in Charleston, according to his prepared remarks. "They are harvested only once they have been planted."
The speeches come amid intensifying criticism of what many say is incendiary rhetoric by Trump following back-to-back mass shootings this past weekend.
The president, who has insisted he is not a racist, said Americans must "condemn racism, bigotry and white supremacy" in a speech to the nation on Monday.
On Saturday, a gunman killed 22 people in El Paso, a Texas city on the border with Mexico. Law enforcement agencies say he was driven by hatred for Hispanics, citing an online manifesto apparently written by the shooter that was rife with anti-immigrant hatred.
In the second mass shooting 13 hours later, a gunman in Dayton, Ohio, fatally shot nine people, including his sister, before he was killed by police.
Trump's rhetoric, including calling Central Americans trying to enter the United States "an invasion," and his hard-line immigration policies have exposed him to condemnation since the El Paso shooting.
"How far is it from Trump's saying this 'is an invasion' to the shooter in El Paso declaring 'his attack is a response to the Hispanic invasion of Texas?' Not far at all," Biden was expected to say.
Trump aides deny his rhetoric was a cause of the shootings. In his national address, the president proposed reforming mental health laws, working with social media to detect possible mass shooters and keeping guns away from people considered potentially violent. But he stopped short of calling for major gun law reforms.
He plans to visit El Paso and Dayton on Wednesday.
Biden and Booker are among 24 candidates trying to become the nominee to take on Trump in next November's election.
Most of the Democrats have called for stricter gun laws, including universal background checks for purchases and banning assault-style weapons; Booker has also proposed requiring licenses to own firearms.
Biden was expected to invoke the rhetoric of previous Republican and Democratic presidents, including Republican George W. Bush and Democrat Bill Clinton, who he said "opposed hate".
In Iowa, Biden planned to say, "we have a president who has aligned himself with the darkest forces in the nation. We have a president with a toxic tongue who has publicly and unapologetically embraced a political strategy of hate, racism, and division."
In his prepared remarks, Booker rejected the debate over whether Trump is a racist, saying that what really matters is how people intend to address the problem.
"If the answer to the question, 'Do racism and white supremacy exist?' is yes, then the real question isn't who is or isn't a racist - but who is and isn't doing something about it," he planned to say.