London (CNN)Drones used by UK police forces are falling out of the sky when it rains, a report by the country's Air Accidents Investigation Branch has found.
Last year, 16 "Matrice 200" series drones produced by Chinese manufacturer DJI crashed due to "technical failures," the report, released Thursday, found.
It notes that in some instances the drones were being used by UK police forces and emergency services at the time of the crashes.
On its website, DJI describes the drones, which weigh 8 pounds and measure just under 28 inches, as "built to endure" strong winds and sub-zero temperatures.
"The new dual-battery power system automatically heats batteries when flying in sub-zero temperatures, while an enclosed design ensures weather and water resistance, so you can fly in a wide range of environments," DJI says on its website.
However, according to the AAIB, "the DJI Matrice 200 series aircraft crashed whilst operating in rain."
"Failures of the Matrice 200 series aircraft resulted in a loss of power and control, with the aircraft typically falling vertically to the ground," the AAIB found.
"This poses a risk of injury to people on the ground which is not mitigated by the current UK regulations or published guidance material applicable to operating an unmanned aircraft system," it added.
In one incident, a DJI Matrice 210 drone being operated by police in Leicester, England "started to spin rapidly and fell to the ground" after earlier ascending 90 meters (295 feet) in the air during a spell of rain, the report noted.
In the report, the AAIB has recommended that the Civil Aviation Authority -- the UK's aviation regulator -- notify users of Matrice 200 series drones of "the possibility of moisture entering the aircraft when operating in rain and that this could result in a sudden loss of control of the aircraft."
In a statement issued to CNN, DJI said safety was its priority and it took "events regarding failures" seriously.
"The DJI Matrice 200 Series has been independently certified by a third party that it has an IP43 rating," it said. "This certifies that 'water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect'. However, the M200 is not suitable, and should not, be operated in conditions or precipitation greater than those stated by the certification.
"All users of M200 series drones should refer to our current maintenance guidelines and safety information here to help manage their aircraft and maximise flight safety."
According to its website, DJI supplies drones to several policing divisions in the UK and elsewhere.
Drones are used by law enforcement all over the world, and can be used in emergency response and firefighting.