MANILA - The Philippines will take legal action against China over its alleged mass harvesting of giant clams in Scarborough Shoal off the South China Sea, Foreign Affairs Secretary Teodoro Locsin Jr. said Tuesday.

Filipino fishermen told ABS-CBN News that the Chinese Coast Guard drives them away from the resource-rich shoal while wooden trawlers bearing the Chinese flag extract giant clams there.

• EXCLUSIVE: Chinese harvesting giant clams in Scarborough Shoal

"We just caught them doing that recently, filed a diplomatic note, and will be taking legal action. With our legal department now," Locsin said in reply to a Twitter follower who shared a link to the ABS-CBN report.

Locsin's statement comes just hours after he said that the time is "not right" for the Philippines to dredge up its territorial dispute with China.

Former Foreign Affairs Secretary Albert Del Rosario over the weekend urged the government to bring up a United Nations-backed arbitral tribunal’s ruling that invalidated Beijing's sweeping claim to the South China Sea, following reports of the increased presence of Chinese vessels there.

"This is actually not the right time to bring up disagreements over the South China/West Philippine Sea with both sides hot under the collar while a pissing contest is in full flower," Locsin tweeted late Monday.

Beijing refuses to recognize the ruling that invalidated its claim to around 90 percent of resource-rich South China Sea.

In December 2016, Duterte said he would "set aside" the arbitral ruling as he sought closer ties with China.

Presidential Spokesperson Salvador Panelo maintained that Duterte "never shelved", but rather "effectively" invoked the arbitral victory.