One of President Trump's GOP primary opponents called on members of the new administration, including the president, to "be on the same page" and avoid inconsistent statements that are troubling to foreign allies.

Ohio Gov. John Kasich said Sunday that allies at the Munich Security Conference are still worried about the support for NATO by President Trump himself, despite repeated reassurances at the conference from several top members of the administration, including Vice President Mike Pence, Homeland Security Secretary John Kelly and Defense Secretary Jim Mattis.

"What they're saying is we can hear from the vice president, Gen. Matts, Gen. Kelly, but we're not sure about the president. It is vital that the administration be on the same page," Kasich said on CNN's "State of the Union."

The U.S. involvement in NATO has been a key issue at the Munich Security Conference, with Pence talking about an "unwavering" commitment to the alliance. But the president himself has wavered in his support, at one point saying that the U.S. may not fulfill its promise to defend other allies of those countries don't increase their monetary support of NATO.

"It's just critically important that all the signals coming out of the administration are very solid and very consistent that we all stand together in Western alliance," Kasich said.