Republican National Committee was reportedly "getting ready to treat me unfairly — big spending planned against me."
"That wasn't the deal!" Trump exclaimed.
The "deal" was an apparent reference to the pledge Trump signed in September to not launch an independent presidential campaign should he lose the nomination.
At the time, Trump said that he was happy to sign the nonbinding pledge because the RNC assured him that it would treat him "fairly."
But Trump's tweet on Monday suggested that he could be trying to use a third-party run as leverage against the RNC again.
And then there is this exchange with Liz Mair, a former RNC online-communications director, who is reportedly spearheading the attack against Trump:
A woman who got fired after two days of working with Scott Walker - a wacko - now trying to raise funds to fight me.— Donald J. Trump (@realDonaldTrump) November 21, 2015
.@realDonaldTrump Thanks for raising my profile & name ID, Donald.I miss you (really!) on The Apprentice! Hope to get you back there soon :)— Liz Mair (@LizMair) November 21, 2015