Facebook says it will stop spending money to fight a proposed California ballot initiative aimed at giving consumers more control over their data.

The measure, known as the "California Consumer Privacy Act," would require companies to disclose upon request what types of personal information they collect about someone and whether they've sold it. It also would allow customers to opt out of having their data sold.

The company made the announcement Wednesday as chief executive Mark Zuckerberg underwent questioning from Congress about the handling of user data.

Pressure has mounted on Facebook to explain its privacy controls following revelations that a Republican-linked firm conducted widespread data harvesting.

Facebook had donated $200,000 to a committee opposing the initiative in California - part of a $1 million effort by tech giants to keep it off the November ballot.

Facebook said it ended its support "to focus our efforts on supporting reasonable privacy measures in California."

Proponents of the ballot measure applauded the move.

"We are thrilled," said Mary Ross, president of Californians for Consumer Privacy.

The California Chamber of Commerce and other groups are fighting to keep the measure off the ballot through the "Committee to Protect California Jobs." Google, AT&T, Verizon and Comcast also contributed $200,000 each to that effort in February.

Committee spokesman Steve Maviglio said the measure would hurt the California economy.

"It is unworkable and requires the internet in California to operate differently - limiting our choices, hurting our businesses, and cutting our connection to the global economy," he said.