The view from Comb Ridge is pictured in Utah's Bears Ears area of the Four Corners Region, Utah, US December 18, 2016. Picture taken December 18, 2016. [Photo/Agencies]

When Republican Congressman Jason Chaffetz of Utah introduced legislation last month to transfer about 3 million acres offederally-held public land to state control, he was bombarded by thousands of angry phone calls, letters and social media postsurging him to back off.

The pressure came not only from liberal environmentalists –but also from gun-toting, often conservative outdoors enthusiasts who are central to Chaffetz’ political base. Both camps fear that transferring federal lands to state control could open them up to drilling and coal mining rather than recreation and preservation.

"I hear you," Chaffetz wrote in a post on his Instagram account announcing the withdrawal of the bill. "I am a proud gunowner, hunter and love our public lands."

Chaffetz's office did not respond to requests for comment onhis reversal.

Outdoor sporting groups - long associated with conservatism because of their support for guns rights and small government -are now collaborating with the environmental left to fight U.S.

President Donald Trump's push to open more public lands toenergy development. Such areas include national forests, parksand Native American tribal territories and account for about one fifth of the United States.

Recent funding data from the Foundation Center database,which aggregates information from tax filings, shows groups such as the Backcountry Hunters and Anglers and the Outdoor Alliancehave accepted grants from big environmental and liberal foundations, including the Turner Foundation and the William and Flora Hewlett Foundation.

The Hewlett Foundation gave $100,000 in 2015 to Backcountry,a conservation group created in 2004. The money accounted formore than two-thirds of its foundation grants that year, and Backcountry told Reuters it is an annual gift with no conditions.

Hewlett said it supports Backcountry because of its"critical work to preserve America's outdoor heritage of huntingand fishing and protect wild places."

The Turner Foundation gave an unrestricted donation of$100,000 to the Outdoor Alliance in 2015, the group's onlyfoundation grant that year.

"Conservation is a nonpartisan issue, and it is a shame itis being politicized," said Judy Adler, president of the TurnerFoundation.

The Environmental Policy Alliance, a pro-development organization, has said environmentalists finance sportsmens'groups as a way to provide conservative cover for a liberal agenda - turning the outdoors groups into “green decoys.”

The alliance, which says it aims to "uncover the funding and hidden agendas" of environmentalists, did not respond torequests for comment.

Highlighting the odd-bedfellows nature of such collaborative lobbying, the Backcountry Hunters and Anglers counts the president's son, Donald Trump Jr., as a lifetime member.

Officials at the Trump Organization, where Donald Trump Jr. is an executive, did not respond to requests for comment. A Trump administration official declined to comment.

Trump has made previous statements opposing the transfer offederal land to states, but has strongly supported more energy development in such areas.