I don't think that this will trigger any shooting, but they are clearly trying to provoke China.
The United States pledged on Tuesday its "enduring commitment" to helping the Philippines, as the longtime allies began naval exercises amid a simmering maritime row with China.
Two state-of-the-art US missile destroyers sailed into Philippine waters to kick-start 11 days of training, which will take place close to the much coveted South China Sea that is the focus of regional tensions.
Both sides emphasised the event was an annual one aimed at deepening defence ties, and not linked to the rising concern in Manila about allegedly aggressive Chinese actions in the strategic and potentially resource-rich South China Sea.
"CARAT was planned in advance... the issue in the South China Sea started in February," Philippine Navy vice-commander Rear Admiral Orwen Cortez said at an opening ceremony for the event, referring to it by its acronym.
"CARAT has nothing to do with the issue."
Nevertheless, the exercises were portrayed as a show of unity between the Philippines and its former colonial ruler.
"The challenges to both our navies, man-made and natural, are many and we should be prepared to address those challenges," Cortez said.
Commander of the US 7th Fleet, Vice Admiral Scott Van Buskirk, described America and the Philippines as "allies" and said "that is the strongest and most enduring commitment the two nations can make."
"Our alliance is underpinned by a deep and abiding US interest in the freedom and security of the Republic of the Philippines," he added.
Philippine President Benigno Aquino this month called for US help in containing China's South China Sea ambitions, saying his country was too weak to stand up to the Chinese alone.
Aquino made his plea to the United States after accusing China of inciting at least seven recent incidents in the disputed waters, including one in which a Chinese vessel allegedly opened fire on Filipino fishermen.
Aquino also accused China of breaking international law by entering the Philippines' 200-nautical-mile economic exclusion zone.
US Secretary of State Hillary Clinton last week offered the Philippines' some comfort, pledging that the superpower would help to modernise the cash-strapped Philippine military.
"We are determined and committed to supporting the defence of the Philippines," vowed Clinton.
At the sidelines of the opening ceremony, Cortez said the Philippine military was hoping it could lease more modern equipment from the United States rather than relying on old surplus US weaponry.
China, the Philippines, Vietnam, Brunei, Malaysia and Taiwan have overlapping claims to parts of the South China Sea, which is believed to have vast oil and gas deposits, while its shipping lanes are vital for global trade.
Vietnam as well as the Philippines have in recent months accused China of taking increasingly aggressive actions in staking its claim to the disputed waters and its archipelagos.
In response, China has insisted it wants to resolve the territorial dispute peacefully but remained firm in its claims to most of the South China Sea, even waters within the Philippines' economic exclusion zone.
Tuesday's opening ceremony for the naval exercises took place at a military base in Puerto Princesa, the capital of Palawan, a narrow island that divides the South China Sea to the west and the Sulu Sea in the east.
The exercises, called Cooperation Afloat Readiness and Training (CARAT), will take place in the Sulu Sea.