WASHINGTON — A chief sponsor of a bipartisan Senate deal to curb the growth of health insurance premiums said Wednesday President Donald Trump called to offer encouragement, a day after the president spoke favorably of the pact but then reversed course.

The mixed signals from the White House have created confusion even as voters face the prospect of dramatic premium spikes absent congressional action.

“I think he wants to reserve his options,” Republican Sen. Lamar Alexander of Tennessee told an Axios forum on Wednesday after the president’s call. Alexander said Trump wanted “to be encouraging,” and the senator predicted that his deal would pass “in one form or another” by year’s end.

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But that outcome looked increasingly uncertain in face of conservative backlash to the deal and Trump’s own erratic signals.

Trump tweeted Wednesday morning: “I am supportive of Lamar as a person & also of the process, but I can never support bailing out ins co’s who have made a fortune w/ O’Care.”

Trump stopped federal payments to health insurers last week that keep costs down for low-income consumers. Alexander and Sen. Patty Murray, D-Wash., announced a deal on Tuesday to restore them along with changes to give states more flexibility.