WASHINGTON - Alarmed by increasing encounters between small drones and manned aircraft, drone industry officials said Monday they are teaming up with the government and model aircraft hobbyists to launch a safety campaign.

The campaign includes a website - www.knowbeforeyoufly.com - that advises both recreational and commercial drone operators of Federal Aviation Administration regulations and how to fly their unmanned aircraft safely. The campaign was announced by the Association for Unmanned Vehicle Systems International and the Small UAV Coalition, both industry trade groups, and the Academy of Model Aeronautics, which represents model aircraft hobbyists, in partnership with the FAA.

The two industry trade groups also said they plan to distribute safety pamphlets at industry events and are working with drone manufacturers to see that safety information is enclosed in the packaging of new drones.

Retailers say small drones, which are indistinguishable from today's more sophisticated model aircraft, are flying off the shelves this Christmas.

"In just a few days, kids old and young will unwrap presents, and many of them - maybe tens of thousands - will have unmanned aircraft," Michael Toscano, president of the unmanned vehicle association, said in a conference call with reporters. "This technology is very accessible and in very high demand, but information on how to fly safety isn't readily available. That's why we've created this safety campaign."

The FAA is concerned that amateurs are using the drones recklessly, increasing the likelihood of a collision that could bring down a plane or rain debris down on people. The agency has been receiving about 25 reports per month this year of drones sighted flying near manned aircraft or airports, up from just a handful of reports two years ago.

Small drones are available today for as little as under $100. As of the end of 2013, about one million small drones had been sold worldwide for recreational and commercial use, according to industry estimates. Sales this year are expected to significantly outdistance previous tallies. Catalogs like Hammacher Schlemmer and Brookstone have prominently featured small drones this Christmas, while online retailer Amazon is offering more than a dozen models priced from as little as $30 to nearly $3,000.

"Many of these operators have no aviation history, background, or knowledge," Margaret Gilligan, FAA's associate administrator for safety, told a recent forum hosted by the Air Line Pilots Association.

Such operators don't intend to interfere with manned aircraft, but "they just don't know what they don't know," she said.

In response to safety concerns, Amazon created a special page on its website with safety information for drone customers. Many small drones can fly only as high as a few hundred feet, which keeps them below most manned aircraft. But some drones on the market are capable of reaching altitudes as high as 18,000 feet - the start of "class A" airspace, where most passenger and cargo airlines cruise.