Flights of more than 400 US Army CH-47 Chinook attack helicopters have been suspended due to a series of engine fires, The Wall Street Jourmal reported, citing US officials.

According to the publication, engine fires occurred in recent days due to fuel leaks, as a result of the incidents no one was injured.

Under suspicion are low-quality O-rings, which could be installed on more than 70 machines of this type during scheduled maintenance. However, as a precaution, the command decided to stop the flights of all Chinooks until the reasons were finally clarified.

The landing of Chinook helicopters, which have been used on the battlefield since the 1960s, could create logistical problems for US soldiers, depending on how long the order lasts.