WASHINGTON (Reuters) - An estimated 40 U.S. state attorneys general will participate in a probe of Facebook Inc, a source said on Monday, suggesting many more states want allegations of anticompetitive practices at the social media company investigated.

FILE PHOTO: Stickers bearing the Facebook logo are pictured at Facebook Inc's F8 developers conference in San Jose, California, U.S., April 30, 2019. REUTERS/Stephen Lam/File Photo

The probe of Facebook, announced in September, is led by New York and includes Colorado, Florida, Iowa, Nebraska, North Carolina, Ohio, Tennessee and the District of Columbia.

Some states, particularly New York and Nebraska, have raised concerns that Facebook and other big tech companies engage in anti-competitive practices, expose consumer data to potential data breaches and push up advertising prices.

Several state attorneys general met on Monday with officials from the Justice Department and the Federal Trade Commission, New York Attorney General Letitia James said in a statement.

The group met with U.S. Attorney General William Barr to discuss the Facebook probe, as well as with Deputy Attorney General Jeffrey Rosen and Makan Delrahim, who heads the department’s Antitrust Division, two sources said.

“Today, we held bipartisan conversations with attorneys general from around the country and key officials at both the U.S. Department of Justice and the Federal Trade Commission about our investigation into Facebook,” James said.

Nebraska Attorney General Doug Peterson was also present and issued a similar statement.

Florida Attorney General Ashley Moody, whose state is one of the leads on the probe, North Carolina Attorney General Josh Stein, and Iowa Attorney General Tom Miller also attended the meetings, their offices said.

The meeting came after Reuters and other outlets reported on Sept. 25 that the Justice Department would open an antitrust investigation of Facebook, which also faces probes by the Federal Trade Commission and the House of Representatives Judiciary Committee.

Following the meetings with top Justice Department officials, the state attorneys general met with department staffers, one source said.

Facebook, which owns one-time rivals Instagram and WhatsApp and has 2.4 billion monthly users, agreed in July to pay a $5 billion FTC settlement for various privacy violations.

Reuters and others reported in June that the Justice Department and FTC had divided responsibility for the companies being investigated, with the Justice Department taking Alphabet Inc’s Google and Apple Inc while the FTC looked at Facebook and Amazon.com Inc. The Justice Department later said it was opening a probe of online platforms, which would include Facebook.

The Washington Post was first to report that the group was likely to expand sharply.