In the U.S. presidential race, the Democratic contenders are preparing for an important primary showdown in South Carolina Saturday, while the Republican candidates face a major test in Florida on Tuesday. VOA National correspondent Jim Malone has the latest from Washington.

South Carolina will be the first southern test for the Democrats and features a large bloc of African-American voters.

Senator Barack Obama is counting on strong African-American support to regain some momentum in the Democratic race after two straight wins in New Hampshire and Nevada by Senator Hillary Clinton.

The tone of the Democratic race has turned more negative following Monday's contentious debate in South Carolina.

Senator Clinton and her husband, former President Bill Clinton, have stepped up their attacks on Obama's record in recent days, and Obama has seemed frustrated at times in trying to respond, especially to those leveled by the former president.

Obama was asked about that on NBC's Today program.

"He is not getting to me," he said. "It is just that I think, in the Clinton campaign, they have had former President Clinton delivering a bunch of inaccurate statements about my record. So naturally, I have got to make sure that those are corrected.

Obama says the Clintons are distorting his record and twisting some of his statements to score political points.

In Monday's debate, Hillary Clinton said Obama has a long record of confusing statements, especially on the war in Iraq.

"It is sometimes difficult to understand what Senator Obama has said because as soon as he is confronted on it, he says that is not what he meant," she said.

Clinton picked up a potentially helpful endorsement Wednesday from Pennsylvania Governor Ed Rendell. Pennsylvania holds its presidential primary on April 22.

The race for the Republican Party's presidential nomination is also intensifying in advance of next Tuesday's primary in Florida.

Four Republican contenders are hoping for a strong showing in Florida, including Senator John McCain of Arizona, former New York City mayor Rudy Giuliani, former Massachusetts Governor Mitt Romney and former Arkansas Governor Mike Huckabee.

Presidential contenders in both parties are focused on economic concerns at the moment.

Romney emphasized his background as a businessman.

"I think it is important to have somebody who has actually spent time in the real economy," said Romney. "I spent my life in the real economy."

McCain talked about the need for tax and budget cuts to stimulate economic growth.

"We have to cut spending," said McCain. "We have to cut the corporate tax rate from 35 [percent] to 25."

McCain has picked up the endorsement of retired Army General Norman Schwarzkopf, who commanded U.S. forces in the 1991 Persian Gulf war.

After the contests in South Carolina and Florida, the presidential contenders from both parties will focus on the so-called Super Tuesday schedule of primaries and caucuses involving more than 20 states that will take place on February 5.