The U.S. and the Philippines began one of their biggest joint military exercises in the last 15 years on Monday. The annual drills -- named "Balikatan" -- would take place over a span of 10 days and witness the involvement of over 11,000 American and Filipino soldiers.

“We make no pretense that we are helping the Philippines as it fields a minimum credible defense,” Philip Goldberg, the U.S. ambassador to the Philippines, reportedly said at the opening ceremony of the drills. “The U.S. is committed to its alliance ... and the U.S. will defend the important principles of freedom of navigation in the air and the sea.”

The drills, part of the U.S. military’s “Pacific Pathways” strategy, which aims to bolster its presence in the region, come at a time when territorial tensions between the Philippines and China have witnessed an upsurge. The dispute between the two Asian nations centers on the status of the Scarborough Shoal -- known as Huangyan Island in China -- located nearly 100 miles from the Philippines and 500 miles from China.

The U.S. had earlier warned China not to ignore the legitimate demands of the countries it is in conflict with in the South China Sea. "Just because the Philippines or Vietnam are not as large as China doesn't mean that they can just be elbowed aside,” U.S. President Barack Obama said, earlier this month.

However, repeated statements by U.S. officials have failed to deter China’s territorial ambitions. Recent satellite images have shown that China has begun construction of an airstrip on the northeastern side of Fiery Cross Reef, which is a part of the Spratly Islands chain claimed by at least three other countries.

“We have compelling reasons to raise our voice to tell the whole world the adverse effects of China's aggressiveness that has created tensions not only among the countries who have overlapping claims in the area,” Philippine military chief Gen. Gregorio Pio Catapang reportedly said, shortly before the start of the drills.