Republican US presidential candidate Ted Cruz stands with Carly Fiorina after he announced Fiorina as his running mate at a campaign rally in Indianapolis, Indiana, United States April 27, 2016. [Photo/Agencies]

WASHINGTON - The US Republican presidential contender Ted Cruz on Wednesday picked former technology executive Carly Fiorina as his running mate, in his last-ditch bid to block frontrunner Donald Trump.

"After a great deal of consideration and prayer, I have come to the conclusion that ... I will run on a ticket with my vice presidential nominee Carly Fiorina," Cruz told a rally in Indianapolis.

Cruz praised Fiorina, the former presidential candidate and Hewlett-Packard chief executive, as "superbly skilled, superbly gifted at helping unite this party."

Fiorina, 61, dropped her White House bid in February. She endorsed Cruz a month later.

"Ted could not be more right in what he said: There is a lot at stake, and in fact, this is a fight," Fiorina said, adding she had tough fights all her life.

But Mr. Cruz's future doesn't look promising after being mathematically eliminated from achieving the delegates needed to win the GOP presidential nomination outright.

Analysts said Cruz was simply trying to regain momentum by announcing his pick for a vice president so early in the race, especially after Trump triumphed on Tuesday with a sweep of five East Coast states.

Trump responded to Fiorina's selection by tweeting a video clip Wednesday in which Fiorina criticized Cruz in a CNN interview earlier this year. "Ted Cruz is just like any other politician: he says whatever he needs to say to get elected," Fiorina said.

"Agreed!" Trump noted under the clip.