President Donald Trump launched a program on Wednesday to expand testing of drones to include flights over people, nighttime operations and flights out of sight of the operator, the White House said.

The pilot program aims to speed up the integration of unmanned aerial vehicles into the national airspace system and test drone detection and tracking while waiving some limits on their use.

Under a memorandum signed by Trump on Wednesday, states and local governments would be able to seek Federal Aviation Administration approval for testing and expanded use. The White House stopped short of proposing new regulations that would allow broader nationwide use of drones or any timetable for new authority.

White House adviser Michael Kratsios told reporters the "program will open the skies for delivery of life-saving medicines and commercial packages, inspections of critical infrastructure, support for emergency management operations."

Kratsios said the program would allow companies and governments to operate drones in ways that are currently restricted by the FAA "including beyond-visual-line-of-sight flights, nighttime operations, and flights over people."

Alphabet Inc and Amazon.com Inc are among a growing number of companies hoping to make package delivery by drones a reality.

The memo said the Transportation Department could allow drone flights at up to 400 feet with the goal of approving at least five pilot projects. The program would expire in three years.

In 2016, the Obama administration opened the skies to low-level small drones for education, research and routine commercial use, but left in place significant restrictions.

The FAA estimates by 2021 the fleet of small hobbyist drones will more than triple and commercial drones will grow tenfold to about 442,000.

In June, Trump told drone executives the administration wants "to create new companies and lots of jobs... We're going to give you the competitive advantage that you need."

In attendance were chief executives of drone companies including Kespry Inc, AirMap, Airspace Inc, Measure UAS Inc, Trumbull Unmanned, and Precision Hawk Inc.

Drone manufacturers have argued that the administration should move faster to approve broader commercial use of drones and noted that the Transportation Department does pre-approve self-driving vehicle technologies.

But security concerns remain.

In September, a civilian drone struck and damaged a U.S. Army Black Hawk helicopter near Staten Island, New York.

This month, a drone hit an airplane landing at a Quebec City airport, the first time an unmanned flying object collided with commercial aircraft in Canada.

The FAA has banned drone flights over 133 U.S. military facilities and over 10 U.S. landmarks, including the Statue of Liberty in New York and Mount Rushmore National Memorial in South Dakota, at the request of national security and law enforcement agencies.

The memo said that the Transportation Department would coordinate with the Defense Department, Homeland Security and Justice Department to consider public safety and national security risks in approving pilot projects.

The Commercial Drone Alliance said it was "optimistic that the program will become a model for overcoming some of the hurdles keeping the full potential of commercial drones from being realized."

Senator John Thune, a Republican, said the new policy "provides sensible direction that promotes drone safety, innovation, and local input."