[Donald Trump]AP Photo/Charles Rex Arbogast Donald Trump released a sharp retort Tuesday to Ted Cruz's lengthy teardown of the Manhattan billionaire earlier in the day. "Ted Cruz is a desperate candidate trying to save his failing campaign," Trump wrote in the statement sent out by his campaign. "It is no surprise he has resorted to his usual tactics of over-the-top rhetoric that nobody believes." He added that Cruz was "unhinged" and that the "stress of losing" was hurting him. He said the "outburst" proved that Cruz didn't the "temperament" to serve as president. "Over the last week, I have watched Lyin’ Ted become more and more unhinged as he is unable to react under the pressure and stress of losing, in all cases by landslides, the last six primary elections --- in fact, coming in last place in all but one of them," Trump wrote. "Today’s ridiculous outburst only proves what I have been saying for a long time, that Ted Cruz does not have the temperament to be President of the United States." The latest war of words between the two Republican candidates came the day of what could be a do-or-die primary for Cruz in Indiana. Earlier on Tuesday, Cruz railed against Trump in one of his harshest attacks to date on the GOP frontrunner, who held a big lead in Indiana polls ahead of the Tuesday vote. "This man is a pathological liar. He doesn't know the difference between truth and lies," Cruz said at a press conference. "He lies — practically every word that comes out of his mouth." [Ted Cruz]AP Photo/Charles Rex Arbogast In the broadside, Cruz called Trump a "narcissist" and "serial philanderer" and said "morality doesn't exist" for him. The comments came in apparent response to Trump's suggestion from early Tuesday morning that Cruz's father, Rafael Cruz, was somehow linked to Lee Harvey Oswald, the assassin of President John F. Kennedy. "This is nuts," Cruz said, sarcastically adding: "Yes, my dad killed JFK. He's secretly Elvis. And Jimmy Hoffa is buried in his backyard." Trump floated the suggestion during a Fox News interview where the real estate magnate cited a dubious National Enquirer article. The tabloid endorsed Trump earlier this election cycle and has published a series of suspect and unverified stories critical of the Texas senator and his family, including one that Cruz accused of being fomented by Trump's "henchmen." Cruz also brought up Trump's retweet earlier this year of an image comparing Heidi Cruz to Trump's wife, Melania Trump. "Apparently she's not pretty enough for Donald Trump," he said. "I may be biased, but I think if he's making that allegation, he's legally blind." But when pressed by reporters as to whether he'd support Trump if he were to be the GOP nominee, Cruz refused to respond. READ TRUMP'S FULL STATEMENT BELOW: Ted Cruz is a desperate candidate trying to save his failing campaign. It is no surprise he has resorted to his usual tactics of over-the-top rhetoric that nobody believes. Over the last week, I have watched Lyin’ Ted become more and more unhinged as he is unable to react under the pressure and stress of losing, in all cases by landslides, the last six primary elections --- in fact, coming in last place in all but one of them. Today’s ridiculous outburst only proves what I have been saying for a long time, that Ted Cruz does not have the temperament to be President of the United States. NOW WATCH: FORMER GREEK FINANCE MINISTER: Why Hillary Clinton is a 'dangerous person'