In a potentially serious setback for expanded commercial drone operations, a federal advisory panel has failed to agree on proposals to identify and track unmanned aircraft nationwide.

The committee, which presented its recommendations to aviation regulators earlier this month, couldn’t reach consensus on basic questions regarding categories of drones that should require such remote monitoring, according to these officials.

As a result, officials familiar with the details said, it’s likely to be more difficult for the Federal Aviation Administration to implement rules acceptable to law-enforcement agencies, hobbyists who fly model airplanes and drone proponents eager to open up U.S. airspace for more  uses.

A majority of the committee did conclude that technology currently exists —or can be devised relatively quickly—to deal with one of the most vexing problems impeding acceptance of small drones weighing several or dozens of pounds: detecting and tracing low-altitude flights that typically occur outside normal ground-radar coverage.

For larger drones flying at higher altitudes, it’s expected to take at least two  or three more years to develop technical standards for communication links and collision avoidance technology.

The nonbinding report emphasizing smaller drones, drafted by nearly 50 industry, labor and law-enforcement experts, hasn’t yet been made public. But according to industry officials, FAA leaders have told panel members the agency may reconvene the group in a bid to achieve more-unified results.

In a statement Monday, the FAA said it “will review the advisory committee’s report and its findings carefully.” A spokesman declined to elaborate.

The split recommendations, however, represent a setback for the agency because chief Michael Huerta recently described the panel as an important building block to end the regulatory logjam confronting the agency and industry champions. Calling the recommendations “absolutely critical” to reaching consensus on major regulatory matters, Mr. Huerta told a drone conference in Las Vegas last month: “I can’t stress how important this work is.”

Senior law-enforcement and national security officials, including leaders of the Federal Bureau of Investigation, have blocked moves to roll out new commercial-drone applications, including flying beyond sight of operators, until acceptable tracking safeguards are in place. The concerns focus on how to pinpoint and electronically follow flights, especially at night or over populated areas, that may pose threats to public safety.

In recent months, U.S. military and antiterrorism officials have stepped up public warnings about dangers of drones being used as weapons against Americans. “There are bad actors out there who want to use them for nefarious purposes,” according to Mr. Huerta.

One faction of the panel wants to see practically all drones subject to tracking requirements. Another segment wants to exclude most model aircraft operated by hobbyists, a category comprising about 200,000 vehicles Congress previously fenced off from new FAA action. Still other participants favor targeting remote identification requirements primarily on larger, more capable models optimized for longer flights, autonomous operations or advanced imaging.

The final report was endorsed only by about half of the group, with the rest either dissenting or spelling out disagreements with various findings. Typically, the FAA depends on such advisory groups to sort out disputes before submitting recommendations.

According to people familiar with the report, panelists ended up concluding that trajectories of drones could be continuously monitored, from takeoff to touchdown, either by piggybacking on radio signals that already control drone maneuvers or utilizing a separate system relying on cellular phone signals. Certain sophisticated drones would require the redundancy of both types of tracking, according to one industry official.

For simpler drones, the solution largely calls for a software modifications. Relying on cellular signals would be more expensive, complicated and require installation or retrofit of some type of modem to tap into existing networks. Under such circumstances, drone operators also would face the extra expense of paying for connectivity.

Location, speed, heading and altitude—accompanied by information identifying the operator—could be transmitted to central displays available to local police or federal enforcers.

The issue is further complicated because law-enforcement agencies have stressed they need a reliable tracking system able to function in remote areas even when wi-fi signals aren’t available.

Slow progress expanding drone operations across the U.S. is not only frustrating industry, but sparking concerns among White House advisers that big industry players are looking overseas to test package-delivery concepts and other applications that promise major boosts to the economy.

“Other countries are not afraid to race ahead when it comes to enabling drone innovation,” Michael Kratsios, deputy chief of the White House Office of Science and Technology, told a drone conference in San Jose earlier this month. “We want to make it possible for you to design, test and deploy your inventions here in the United States.”

White House officials are drafting plans to “test models for state and local involvement” promoting and overseeing drones, Mr. Kratsios said in his San Jose speech. Some industry officials expect an announcement within days or weeks.

The activity comes amid sharply increasing reports of close calls between drones and manned aircraft in the U.S. and elsewhere.

In the first accident probe of its kind, the U.S. National Transportation Safety Board is looking into a September collision between a small drone and an Army helicopter east of Staten Island, N.Y., which  damaged the chopper’s main rotor and other parts.

Four months earlier, a Swiss International Air Lines jetliner approaching to land at Zurich flew within roughly 30 feet  of a drone, with the pilots having inadequate time to try to avoid it.

One of the threshold questions the FAA is trying to answer focuses on the likely extent of damage to a commercial aircraft in the event of an airborne collision with a drone. Another topic that concerns safety regulators deals with potential injuries to humans on the ground from out-of-control drones, depending on the sizes of the vehicles.