Vermont Sen. Bernie Sanders attacked Democratic front-runner Hillary Clinton over her record on hydraulic fracturing, or fracking, during Thursday’s debate.

Sanders attacked Clinton’s previous promotion of natural gas saying, “[w]hen you were Secretary of State, you also worked hard to expand fracking to countries all over the world.”

Clinton admitted Sanders was correct, but stated during the CNN debate, “I don’t think I’ve changed my view.”

Clinton specifically claimed that “for both economic and environmental and strategic reasons, it was American policy to try to help countries get out from under the constant use of coal, building coal plants all the time, also to get out from under, especially if they were in Europe, the pressure from Russia, which has been incredibly intense. So we did say natural gas is a bridge.”

Clinton promoted fracking for natural gas in other countries during her tenure as secretary of state, saying in 2010, “[t]he United States will promote the use of shale gas.” The Department of State helped advise African and other world leaders on the benefits of fracking during her tenure, connecting them with American energy experts and organized visits to drilling sites in America.

The State Department hosted several conferences on fracking in other countries while Clinton was secretary of state and sent U.S. experts to help foreign officials develop fracking programs. State’s fracking program continued under Secretary of State John Kerry, known as the Unconventional Gas Technical Engagement Program.

Much of the fracking proposed by the Department of State would have been done on public lands in other countries, but Clinton now supports phasing out fracking on public lands in America. Clinton claimed in the debate that by the time the Enviromental Protection Agency finishes regulating fracking, there will be much less of it in America.

The Hillary Clinton campaign immediately hung up when contacted in December by The Daily Caller News Foundation about the presidential candidate’s record on fracking.

Environmentalists have accused Clinton of “soft climate denial” for her fracking history and her criticism of Sanders’ environmental record.

Friends of the Earth Action, which has endorsed Sanders, claimed Clinton lied about the Vermont senator’s environmental record during an interview earlier this month.

Friends of the Earth claims to have “over 2 million members and supporters around the world,” but is poorly funded compared to more established environmental groups. Larger environmental groups, such as the League of Conservation Voters, have endorsed Clinton.

Follow Andrew on Twitter

Send tips to andrew@ dailycallernewsfoundation.org.

Content created by The Daily Caller News Foundation is available without charge to any eligible news publisher that can provide a large audience. For licensing opportunities of our original content, please contact licensing@dailycallernewsfoundation.org.