Sen. Bernie Sanders speaks at a recent campaign rally at the Phoenix Convention Center. (Ricardo Arduengo/AP)

Sen. Bernie Sanders of Vermont continued his intense spending pace in February as he scrambled to catch up with former secretary of state Hillary Clinton in their race for the Democratic presidential nomination, according to campaign-finance details set to be filed Sunday.

Sanders outraised Clinton for the second month in a row, pulling in $43.5 million to her $30.1 million, according to a Sanders campaign official. But the new figures also indicate that he plowed through far more cash, spending $40.9 million to her $34.3 million. That left the senator with $17.2 million in the bank as March began, while Clinton had $30.8 million.

In all, Sanders has raised just under $140 million, powered by nearly 2 million donors who have repeatedly fed the campaign with small contributions online. Clinton, who this month secured her 1 millionth donor, has brought in nearly $161 million overall for her bid.

Anu Narayanswamy contributed to this report.