BERLIN (AP) — Germany's environment minister says he doesn't expect the extraction of natural gas by "fracking" will start any time soon in Europe's biggest economy.

Shale gas is located underground across Europe, but environmental concerns over extracting it are widespread. Hydraulic fracturing, or "fracking," frees natural gas from shale by injecting a well with chemically treated water and sand. Supporters say it can be an economic boon, but critics say it can pollute groundwater.

Environment Minister Peter Altmaier told Deutschlandfunk radio Monday that Germany's government is working to ensure the practice is subject to limits and he wouldn't advise anyone to seek drilling licenses soon.

Altmaier said he "can't see fracking being used anywhere in Germany in the foreseeable future."