The U.S. Federal Aviation Administration said it has expanded the area in North Dakota where research flights of small drones are permitted as the drone industry eagerly awaits rules on commercial use of the unmanned aircraft.

Flights under the auspices of the Northern Plains test site will now be allowed in most of northeastern North Dakota, FAA said in a statement, adding that it soon expects to authorize flights in about two-thirds of the state.

Flight operations at the Northern Plains site, one of six FAA-authorized test sites in the country, began in May and were limited to a small area of several square miles.

The North Dakota flights have initially focused on aiding agricultural research, including checking soil quality and the status of crops.

The six sites have given companies, universities and others a place to test small drones, defined as less than 55 pounds (25 kg), for a variety of uses, including package delivery and aerial surveying.

The FAA is months late in developing small drone regulations. A draft FAA rule, under review by the White House Office of Management and Budget, is expected to be published soon, kicking off a year or two of comment and revisions before it takes effect.

The FAA rules will cover commercial drone uses, which are now mostly banned. They will not apply to hobbyists operating model aircraft. Congress granted these users an exemption from rules in 2012.