Philippine authorities announced the arrest of several Chinese nationals as part of their crackdown on a group allegedly conducting espionage operations.

The National Bureau of Investigation held a joint news conference with the military on Thursday in Manila. The five suspects arrested last week were also present.

The head of the Philippine Armed Forces, General Romeo Brawner, said that authorities had been tracking the network since November.
He stated that the five allegedly used drones to capture images of military facilities and Philippine Coast Guard vessels.
He stressed that the incident is "very dangerous" to national security and could just be the "tip of the iceberg."

The arrests come amid confrontations between Manila and Beijing over territorial disputes in the South China Sea.
Earlier this month, a Chinese citizen along with two Filipinos were arrested on suspicion of surveillance on military facilities. Authorities believe the two cases are connected.