BEIJING, Dec. 31 -- Four people have been detained for navigating an aerial drone near the Beijing Capital International Airport, affecting the normal flights of passenger planes, according to local police on Tuesday.

The four suspects were detained for the crime of endangering public security, according to the police.

They were alleged to have navigated the drone, which was refitted from a model airplane, at about 11 a.m. on Sunday in a surveying and mapping operation to the east of the airport, according to the Beijing police.

They did not apply for approval for their flight operation in advance according to law, caused about 10 passenger flight delays, and forced two planes to avoid collision in the air, according to the police.