UPDATE: 2:20 p.m.
Since Marco Rubio challenged Patrick Murphy this morning to six debates, the U.S. Senate candidates have been trading barbs all day.
Murphy initially responded to Rubio this morning by proposing a counter-challenge -- that Rubio commit to serving a full six-year term, if elected. (It's something that Rubio, as recently as Monday, continues to be vague and non-committal about, prompting criticism that he's already interested in running for president again in 2020.)
Murphy said in a statement he was "excited to debate Marco Rubio" but called Rubio's proposal "nothing more than a desperate attempt to try and change the campaign narrative from the fact that he abandoned Florida."
At a press conference soon after in West Palm Beach, Murphy told reporters he won't commit to the six debates Rubio wants unless Rubio agrees to his counter-challenge.
"I'm going to take his challenge seriously," Murphy said. "We've already agreed to one debate, I'm looking forward to that and our teams are going to continue, you know, talking to hash out the details there. There are going to be multiple debates."
Rubio's campaign then accused Murphy of "ducking debates already."
"Just one day into the general election and Patrick Murphy is already making excuses about ducking debates," Rubio campaign manager Clint Reed said in a statement. "Marco believes Floridians deserve to know where each candidate stands on important issues facing our state and nation, but apparently Murphy doesn't agree. What is he so scared of?"
Rubio's campaign told the Tampa Bay Times today that it had accepted an invitation for a debate, possibly in early October.
Herald reporter Alex Daugherty and Times reporter Alex Leary contributed to this report.
ORIGINAL POST: 8:15 a.m.
Wasting no time after their primary night victories, Republican incumbent U.S. Sen. Marco Rubio challenged Democrat Patrick Murphy this morning to six live, televised debates before the November election.
Rubio said this is what the 2010 candidates agreed to. He wants the media to sponsor the debates, including one by a Spanish-language outlet.
Asked last week about debating Rubio, Murphy said "yes, absolutely" but he didn't commit to any specifics at the time. Murphy said their campaigns would negotiate the details.
Minutes after Murphy's primary race was called last night, his campaign announced a 10 a.m. press conference in West Palm Beach, signaling his own official start to the general election campaign.
Here's Rubio's letter to Murphy today: