The US and the Philippines are set to launch their biggest annual joint military exercises in years, amid growing tensions over China's recent activities in disputed South China Sea waters.
The "war games" beginning on Monday will involve an estimated 12,000 troops - double the number from last year - in simultaneous drills across the Philippines for 10 days.
Analysts have described the drills as a "show of force".
About 6,656 American soldiers will join the exercises, to be supported by 76 US aircraft and three naval vessels, according to reports.
As part of the exercises, American and Filipino troops will carry out naval drills on Tuesday at a base west of the Philippines. The area faces the disputed islands in the South China Sea, where China is reportedly building a runway that could accommodate "any type" of Chinese aircraft.
The Philippines, Vietnam, Malaysia, Brunei and Taiwan also have overlapping claims in the area.
A Philippine military spokesman told reporters in Manila on Sunday that "no specific threat was factored" into the drills.
But in an interview with the AFP news agency last Tuesday, Philippine President Benigno Aquino cautioned of possible military conflict in the region over Chinese activities. He said the latest moves by Beijing "engender fear for the rest of the world".
China's Foreign Ministry spokesman Hong Lei dismissed those claims, saying the Philippines should "respect China's sovereignty".
While the Philippines will not overtly admit that the size of forces involved in the exercises reflects its anxieties over China, it is "replete with intriguing symbols," Alexander Yano, a retired general and former head of the Philippine military, told Al Jazeera.
"It could be viewed as a show of force amidst the ongoing tension," he said. "The significant increase in numbers invariably sends strong signals of overt 'muscle-flexing' particularly by the US, the Philippines' strongest ally.
"The usual line that such moves have nothing to do with the current row in the South China Sea is expected as a diplomatic cloak."
The expanded number of US and Filipino troops participating in the exercises could be "construed as an enhancement in the level of military-to-military engagement" between the two decades-old allies "to address common threats," Yano said.
The US and the Philippines have had a military treaty since 1951. Until 1992, the country hosted two of the largest US military facilities outside the US, until a volcanic eruption and a Philippine senate vote forced the closure of these bases.
But in 1998, US troops returned to the Philippines through a "visiting forces agreement", and in April 2014, during the visit of President Barack Obama, the agreement was expanded to allow more troops in the country for an extended duration.
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Jose Torres, a Filipino journalist who has covered the military, told Al Jazeera the while the Philippines is closely allied with the US, it should "be careful in handling the China issue, and should use all diplomatic channels in dealing with Beijing".
Yano, the US-trained former Filipino general, agreed saying that the Philippine government should work with neighbouring South East Asian countries to address the dispute with China.
But he also said that the Philippines should be self-reliant in defending its borders.
"When push comes to shove, the Philippines should be able to have credible defence in case such contingency arises. Such military preparedness can only be ensured through an honest-to-goodness modernisation programme that should be pursued with urgency."
The latest US-Philippines military exercises also come seven months after a 19-year-old US soldier was accused of killing a Filipino transsexual during a visit in the city of Olongapo north of Manila, near a former US air base. That incident has prompted fresh waves of protests against the military exercises.
Meanwhile, Renato Reyes, head of the leftist group Bayan, said the "war games will not help the Philippines against the expansionist activities of China in the region".
"The US has repeatedly said that it that does not take sides in the maritime dispute," he said, adding that the Philippine national interest "is not identical with US strategic pivot to the region."
Source: Al Jazeera