It comes after a photo of Melania Trump was used by Cruz supporters
US presidential hopeful Donald Trump has switched tactics in his campaign - by comparing his wife to his rivals.
Mr Trump tweeted an unflattering photo of Senator Ted Cruz's wife, Heidi, adding that "A picture is worth a thousand words".
Beside Mrs Cruz in the edited photo is Mr Trump's wife, Melania.
In response, Senator Cruz said: "Donald, real men don't attack women. Your wife is lovely, and Heidi is the love of my life".
Donald, real men don't attack women. Your wife is lovely, and Heidi is the love of my life. https://t.co/pprXhIMzUT— Ted Cruz (@tedcruz) March 24, 2016
While Mrs Cruz, who also has a Twitter account, has not responded to Trump's tweet.
It comes after a photo of Melania Trump - originally shot for GQ Magazine - was used by Cruz supporters online.
It shows her in a nude pose, with the caption: "Meet Melania Trump. Your next First Lady".
Donald Trump attacked Cruz, saying: "Lyin' Ted Cruz just used a picture of Melania from a G.Q. shoot in his ad. Be careful, Lyin' Ted, or I will spill the beans on your wife!"
But Senator Cruz denied having any involvement, replying: "Pic of your wife not from us. Donald, if you try to attack Heidi, you're more of a coward than I thought".