WASHINGTON (REUTERS) - Former Hewlett-Packard chief executive officer Carly Fiorina will launch her campaign for the 2016 US Republican presidential nomination on May 4, the Wall Street Journal reported on Wednesday.

Fiorina will announce her candidacy online and hold a conference call for the media, the newspaper said, citing a person with knowledge of her plans.

She would join US Senators Ted Cruz, Marco Rubio and Rand Paul as declared Republican candidates.

A spokeswoman for Fiorina would not confirm the report but did not deny it either.

"I can only say that we are not confirming this," said Sarah Isgur Flores, who also works on Fiorina's Unlocking Potential Project.

Fiorina has been appearing in states considered key to winning the Republican nomination.

On Wednesday, she visited Iowa to speak in Cedar Rapids and sign advance copies of the book she is releasing on May 5, Rising To The Challenge, according to her Twitter feed.

She also participated in a radio interview with Simon Conway, a conservative talk show host in Des Moines.