NEW YORK — Royal Dutch Shell PLC said Friday it will buy East Resources Inc., a major owner of shale gas holdings in the northeast United States, for $4.7 billion from private investors.

Europe’s largest oil company said it will pay cash for East Resources, a Pennsylvania company that owns more than 2,500 oil and natural gas wells in the United States. It also controls 1.25 million acres of land, mostly in the energy-rich Marcellus Shale region that runs from New York to southwest Virginia.

Shell CEO Peter Voser said the acquisition fit with plans to “grow and upgrade” its holdings of shale gas in North America.

International energy companies have aggressively sought a bigger foothold in the U.S. oil shale industry, even with natural gas prices slumping to less than half of what they were in 2008.

Earlier this year, Japanese energy giant Mitsui & Co. said it would pay $1.4 billion for a stake in Anadarko Petroleum Corp.’s shale assets. India’s Reliance Industries Ltd. also recently paid $1.7 billion for part of Atlas Energy’s shale gas deposits.

Natural gas is expected to be in high demand in coming years as a cleaner burning fuel with lower carbon emissions than coal and other fossil fuels. The nation’s shale deposits are estimated to contain at least a 100-year supply.

Drillers have been especially interested in the Marcellus Shale region. Bank of America Merrill Lynch estimated earlier this year that drillers can turn a profit there even with prices holding at around $4 per 1,000 cubic feet. Natural gas futures closed at $4.34 on Friday.

Still, environmental groups say they’re concerned that chemicals used to extract natural gas from shale could pollute water supplies. They’re pushing legislation that would require drillers to make the chemicals used public.

“It can turn an area into an industrial landscape,” said Jon Jensen, executive director of the Park Foundation, a group of Exxon Mobil shareholders in Ithaca, N.Y., that wants the company to disclose the environmental impacts of shale drilling.

“A single well might not look devastating, but this is really a death by a thousand cuts,” Jensen said.

States in the Marcellus Shale region have tightened environmental regulations to address concerns about potential contamination of drinking water supplies and other adverse effects. In April, New York state announced new regulations that effectively prevent natural gas drilling in the New York City and Syracuse watersheds.