This is the last chance for Cruz.
Cruz is already mathematically eliminated from reaching a delegate majority.
"We're going the distance," Trump rival Ted Cruz said on ABC's "This Week."
Gov. Mike Pence made his support for the Texas senator official.
The New York billionaire scored wins in Pennsylvania, Maryland, Connecticut, Delaware and Rhode Island.
They want to deprive him of delegates.
Trump stressed that he expects to win the number of delegates needed to land the nomination on the first ballot at July's national convention.
Cruz was the only candidate to address the convention crowd in Casper.
Aunque el magnate encabeza la carrera por la nominación presidencial republicana con 742 delegados, existe la posibilidad de que no alcance los mil 237 necesarios para asegurar la nominación
"I actually think that Donald Trump and Ted Cruz have done us a favor," Obama said, referring to policy positions that would restrict Muslims and Mexicans from entering the country.