Editor's note: This story has been updated throughout.
U.S. Sen. Ted Cruz's presidential campaign is officially teaming up with rival John Kasich to deny frontrunner Donald Trump the Republican nomination.
On Sunday night, the two campaigns agreed to a game plan that they hope will deny Trump the 1,237 delegates he needs to clinch the nomination before Cleveland: Cruz will focus on the upcoming Indiana primary, while Kasich, the Ohio governor, will zero in on Oregon and New Mexico.
Abandoning its original plan to campaign in those two later contests, the Cruz campaign will instead "clear the path for Gov. Kasich to compete," Cruz campaign manager Jeff Roe said in a statement.
The development is a major shift in strategy for Cruz, who until now had resisted any coordination with Kasich. The deal comes two days before Trump is poised to sweep five northeastern primaries — and roughly a week after Cruz's path to 1,237 delegates before the convention closed.
Reacting to the deal on Twitter and in a statement, Trump denounced Cruz and Kasich as failed candidates resorting to a desperate act. The agreement, Trump said, is "yet another example of everything that is wrong in Washington and our political system."
"Collusion is often illegal in many other industries and yet these two Washington insiders have had to revert to collusion in order to stay alive," Trump said in the statement. "They are mathematically dead and this act only shows, as puppets of donors and special interests, how truly weak they and their campaigns are."
In statements released moments apart, the Cruz and Kasich campaigns made clear their agreement only extends to the three states. They also urged outside groups, such as super PACs supporting the two candidates, to follow their leads.
New Day for America, the top super PAC supporting Kasich, signaled it was on board. "Of course we will do whatever is best for Gov. Kasich," said Connie Wehrkamp, a spokeswoman for the group.
Trusted Leadership PAC, the main super PAC backing Cruz, did not immediately respond to a request for comment. On Friday, it had announced a $1.6 million spending plan for Indiana that included an anti-Kasich TV ad.
Indiana holds its primary May 3, while New Mexico votes on June 7 and Oregon on May 17.
Cruz is already going all in on the Hoosier State, spending the past two days there despite the looming contests in the northeast. He is scheduled to continue stumping in Indiana on Monday.
In both their statements, the campaigns reiterated long-held concerns about Trump’s viability in November.
“Having Donald Trump at the top of the ticket in November would be a sure disaster for Republicans,” Cruz campaign manager Jeff Roe said. “Not only would Trump get blown out by [Hillary] Clinton or [Bernie] Sanders, but having him as our nominee would set the party back a generation."