Ted Cruz said only he can win the GOP nomination and the general election, but added that John Kasich would also prevail over Democratic candidate Hillary Clinton.

Cruz urged conservatives and "Republican[s] who want to win" to vote in Pennsylvania's primary on Tuesday, during an interview with 1210 WPHT in Philadelphia.

"In order to win, you've got to be able to, number one, win the nomination; number two, win the general," Cruz said. "There are two candidates in this race who can win the nomination: me or Donald Trump. The nominee will be one of the two of us. There are two candidates in this race who can win the general, me and John Kasich. There's only one person who can do both — win the nomination and win the general."

Cruz discouraged voters from supporting Kasich, but took a much harsher line against Trump, who Cruz said would cost Republicans control of the U.S. Senate.

"If Donald is the nominee, every blue-state-and-purple-state-Republican running is in grave jeopardy and there's nothing that can be done about it," Cruz said. "If I am the nominee, [Pennsylvania Sen.] Pat Toomey gets re-elected. If Donald Trump is the nominee, the Senate is gone and there's nothing you can do about it."

Cruz is on the campaign trail in Indiana on Tuesday ahead of next week's primary as he looks for a Midwestern win to blunt Trump's momentum.