Saudi Arabia has banned air traffic controllers from the kingdom’s skies after a spate of deadly air accidents, prompting an investigation by the government’s inspector general.

Air traffic controllers were allowed to operate for only a few hours a day for nearly two months during the coronavirus pandemic, which began in early March.

But the restrictions have now been lifted.

The government’s watchdog agency, the Ministry of Transportation, said the restriction was needed because controllers are required to operate on the same frequency as other operators.

The ministry says that in 2016, at least 2,500 flights were cancelled because of the coronacids, which have killed more than 1,500 people in Saudi Arabia.

The agency has also said that controllers who had previously operated in the country were required to undergo training, as well as a physical exam.

It says the rules were enforced in coordination with Saudi Arabia Transport Minister Adel al-Jubeir, and that the ministry is also reviewing existing regulations.