Ted Cruz speaks to supporters at a rally at Provo High School in Provo, Utah, on Saturday. (The Washington Post)

Sen. Ted Cruz had his costliest month of the presidential campaign in February, spending $17.5 million as he battled front-runner Donald Trump through a series of GOP primary contests, an effort that ran down his cash reserves.

Cruz campaign manager Jeff Roe wrote in a tweet that the senator from Texas raised $11.9 million last month, up from the $7.6 million his campaign collected in January. But Cruz entered March with just $8 million in the bank, down from the $13.6 million he had at the beginning of February.

Roe said the campaign has enough resources to sustain his bid all the way to the California primary.

Cruz is also backed by a dozen independent groups, a chaotic dynamic that nonetheless has provided him with additional firepower. One of the biggest super PACs, Stand for Truth, reported raising nearly $4 million in February. Of that, $1 million was donated by Gale Alger of Palm Beach, Fla., wife of investment-firm founder Fred Alger.

Anu Narayanswamy contributed to this report.