Updated at 4:20 p.m.: Revised to include O'Rourke response.

WASHINGTON -- Sen. Ted Cruz challenged his Democratic rival to five one-hour debates on Wednesday, offering a bold counterstroke to Rep. Beto O'Rourke's sniping that he had been ducking head-to-head confrontation.

"As Senator Cruz has long believed, our democratic process is best served by presenting a clear and substantive contrast of competing policy ideas, and these five debates will be an excellent way for both you and the Senator to share your respective visions with Texas voters in the weeks leading up to the November election," Cruz campaign manager Jeff Roe wrote the El Paso Democrat.

The Cruz campaign shared the letter with news outlets.

"I am encouraged that Sen. Cruz has decided that he's ready to debate the issues. Our campaign looks forward to working with his campaign to finalize mutually agreed upon details," O'Rourke said in a statement issued through an aide.

In April, O'Rourke challenged the senator to six debates, including two in Spanish. The one-term senator, whose father grew up in Cuba, has called his command of the language "lousy" and rejected the idea.

Cruz's proposal calls for English-only debates, in a variety of formats and covering a range of topics. Each would be on a Friday night -- starting in Dallas on Aug. 31 and ending in Lubbock on Oct. 12 -- to accommodate his Senate duties in Washington.

The proposed topics include areas where Cruz might feel he has an advantage -- taxes, trade, foreign policy and the Supreme Court. There are also contentious issues on the list, too, such as health care and immigration. Gun violence is a notable omission.

Two weeks ago, O'Rourke tried to shame Cruz into setting a debate schedule, noting that two months had passed since he had issued his challenge. The Cruz side maintained that the senator was neither stalling nor ducking, he just wasn't ready to set a schedule.

O'Rourke has blistered past the incumbent in fundraising and kept him to a single-digit lead in polls -- not good enough to win, but an unusually strong showing in Texas, where Democrats haven't won a statewide race since 1994.

Cruz has warned supporters by email that the news on the fundraising front is "VERY BAD" and routinely points to his modest lead as reasons for concern. Independent handicappers haven't put Cruz on any endangered list, however.

"He was a Princeton debate champ. This is his thing," O'Rourke said two weeks ago. "I don't in any way think that this would be easy but I do think it's necessary."

But he said, "It's been hard to pin him down."

Cruz's willingness to debate stands in contrast to the refusal of other statewide Republican incumbents to face their opponents, among them Lt. Gov. Dan Patrick, Agriculture Commissioner Sid Miller, and Land Commissioner George P. Bush.

Five debates would be unusual for a Texas Senate race, and a robust number for a Senate contest anywhere. In Virginia, Sen. Tim Kaine --the Democrats' last nominee for vice president -- just took part in the first of three debates he's agreed to ahead of Election Day.

The Cruz letter suggests that topics, sites, time limits and formats are not subject to negotiation, though Roe indicated that he is open to discussion on moderators, sponsors and media partners. The proposal:

Debate 1: Aug. 31 in Dallas on Jobs/Taxes/Federal Regulations/National Economy (podiums)

Debate 2: Sept. 14 in McAllen on Immigration/Border Security/Criminal Justice/Supreme Court (seated)

Debate 3: Sept. 21 in San Antonio on Foreign Policy/National Security (town hall)

Debate 4: Oct. 5 in Houston on Energy/Trade/Texas Economy (podiums)

Debate 5: Oct. 12 in Lubbock on Healthcare/Obamacare (town hall)

As O'Rourke said, Cruz was a top college debater during his years at Princeton. He also has argued nine cases before the U.S. Supreme Court and during the 2016 GOP presidential primary, ran a gauntlet of a dozen debates against Donald Trump and other rivals.

In his 2012 bid for the Senate, Cruz debated then-Lt. Gov. David Dewhurst and other Republicans in the primary, but he declined Dewhurst's proposal for a Spanish-language debate. He participated in at least one televised debate with his Democratic rival, former state Sen. Paul Sadler, at KERA in Dallas.

In March, he parried O'Rourke's taunting over his resistance to setting a debate schedule by noting that he had debated Sen. Bernie Sanders on CNN several times last year -- proving that "I am not remotely afraid to debate left-wing liberal socialists."