PHOENIX (AP) — A bill that would have required law enforcement agencies in Arizona to get search warrants before using unmanned aircraft to gather evidence was stripped Thursday of its key provisions and turned into a measure to create a study committee on drone use.

The decision by Republican sponsor Rep. Tom Forese of Chandler to amend the bill came after law enforcement voiced opposition to the legislation at a committee hearing last month.

Forese said he's also heard from economic development interests who told him they were worried about the bill's impact to the growth of the technology in Arizona.

Arizona officials are hoping the state will be chosen for one of six drone test sites around the country that the Federal Aviation Administration sought proposals for last month. The agency is required by a law enacted a year ago to develop sites where military and civilian drones can be tested in preparation for integration into U.S. airspace.

Privacy advocates are worried that widespread drone use will infringe on civil liberties and lead to constant surveillance of the public.

Thursday's decision by Forese came a day after U.S. Sen. Rand Paul filibustered the confirmation of CIA director-designate Richard Brennan over the administration's refusal to rule out using drone for attacks in the U.S. Sen. John McCain, R-Ariz., ridiculed Paul's concerns Thursday, and attorney General Eric Holder sent a letter to Paul saying it would be illegal to use drones to kill an American here.

The original bill requiring warrants also would require evidence collected without a warrant to be thrown out in court. It contained exemptions allowing drone use without a warrant. One comes into play if the federal Department of Homeland Security determines drones are needed to prevent a terrorist attack. The other kicks in when swift action is needed to prevent an escape, evidence destruction or imminent danger.

Virginia, Missouri, New Jersey, Florida and Hawaii have passed or introduced similar legislation.

Privacy concerns drove Forese's bill, but he said Thursday he's been convinced that a balanced approach is needed. He said the study committee will look at privacy issues created by the potential use of drones as well as the economic development potential of the new technology.

Forese pointed to the state's legacy with aviation and unmanned aviation in particular at military based like Fort Huachuca.

"This is our legacy, this is our rightful opportunity," Forese said. "But at the same time it's a new technology and there is a potential for issues with privacy and the Fourth Amendment and I just think it's worth due diligence."

Forese amended the bill on the House floor Thursday afternoon and it then passed the full House with little opposition. Another House bill on the same topic never advanced out of committee.