Fallout continues for Texas Sen. Ted Cruz after his controversial decision not to endorse Donald Trump for president at the Republican National Convention, as two of the top donors to his presidential campaign issued a strong rebuke against him.

The harsh statement from Robert Mercer and his daughter Rebekah Mercer of Long Island took issue with Cruz's speech and his call for voters to "vote their conscience."

In a rare statement, given to the New York Times, they said:

"Last summer and again this year, Senator Ted Cruz pledged to support the candidacy of the nominee of the Republican Party, whomever that nominee might be. We are profoundly disappointed that on Wednesday night he chose to disregard this pledge."

The statement continued by urging party unity and chastised Cruz, calling the "decision both regrettable and revealing."

The Mercers donated over $11 million to Cruz-affiliated super PACs supporting his presidential campaign.