Donald Trump has called Ted Cruz and John Kasich "totally desperate" after they announced they are joining forces to stop him from winning the Republican presidential nomination.
On Sunday evening, both camps released statements to say they will focus on different states during upcoming primaries to keep Trump out.
Kasich will pull out of Indiana to give Cruz "a clear path" in the May 3 primary, they said. Cruz will "clear the path" for Kasich in Oregon for its May 17 primary and New Mexico for its June 7 primary.
They hope that these efforts will block Trump from gaining the 1,237 delegates he needs to take the nomination. So far he has 845 delegates to Cruz's 559 and Kasich's 148.
"Having Donald Trump at the top of the ticket in November would be a sure disaster for Republicans," Ted Cruz's campaign manager Jeff Roe said in a statement.
He said they were working with Kasich "to ensure that we nominate a Republican who can unify the Republican Party and win in November."
On Sunday night, Trump hit back.
"Wow, just announced that Lyin' Ted and Kasich are going to collude in order to keep me from getting the Republican nomination. DESPERATION!" he tweeted.
He continued: "Lyin' Ted and Kasich are mathematically dead and totally desperate. Their donors & special interest groups are not happy with them. Sad!"
Trump also slammed his rivals in a longer statement on his campaign website Sunday night.
"It is sad that two grown politicians have to collude against one person who has only been a politician for ten months in order to try and stop that person from getting the Republican nomination," the statement said.
"Because of me, everyone now sees that the Republican primary system is totally rigged... This horrible act of desperation, from two campaigns who have totally failed, makes me even more determined, for the good of the Republican Party and our country, to prevail!"