Philippines closely watching China's moves on disputed atoll, wary of militarisation

"Once they build a structure there, that would be a different story. We have several options that we could do. Diplomatically, we could file protests, but we are watching so that we will not have a repeat of Mischief Reef," Brawner told a forum organised by foreign correspondents.

Both China and the Philippines claim the Scarborough Shoal, but sovereignty remains unresolved. China took control in 2012 after a standoff and has since stationed its coast guard and fishing vessels there.