As she picked up a camera lens to zoom in on two specks on the horizon that were racing across the South China Sea towards her boat, Philippine journalist Chiara Zambrano froze in shock.
The wave-piercing hulls and distinctive blue camouflage of China's Houbei Type 22 missile-armed fast-attack crafts were clearly visible.
"I thought 'what the heck?' There was no mistaking it," she told Britain's Daily Telegraph.
Zambrano and her filming crew were aboard a Philippine fishing boat in early April to work on an investigation about the impact on the local population of China's militarisation of the reefs, atolls and waters off the Philippines coast.
China is beefing up its presence in the strategic South China Sea, raising fears it is working to seize control of access to crucial global shipping routes in international waters.
To expand its territorial claims, it has deployed its navy, coastguard and its maritime militia - dubbed China's "Little Blue Men", in reference to the unmarked Russian "Little Green Men" soldiers who appeared in Crimea shortly before President Vladimir Putin annexed the peninsula.
The militia is embedded into China's fishing fleet to intimidate and squeeze out rival South East Asian claimants to the waters.
The United States is challenging China's ambitions with its own patrols, and this week the head of the Navy SEALs said it would pivot away from anti-terror operations in deserts and mountains to focus on "maritime" threats posed by Russia and China.
The UK also plans to stage freedom of navigation operations when it deploys its aircraft carrier strike group to the region later this year.
The news team had first been intercepted and followed by the Chinese coastguard as they approached the Second Thomas Shoal, a feature of the Spratly islands, which are claimed by the Philippines, China, Taiwan, Brunei, Malaysia and Vietnam, and where the Philippine Navy maintains a small presence.
Their vessel had turned back towards shore and was about 90 nautical miles from the Philippines' Palawan province when they were confronted with a more menacing and unprecedented threat of armed attack craft.
"They came in pretty fast," said Zambrano. "They tailed us and split up so we were in an uneven V formation. They were on either side of the back of the boat and they were tailing us for at least 20 minutes," she added.
"At this point I wasn't sure what to do. Were they going to board us? Should I be hiding my memory cards? Those things were running through my mind because there was no precedent to this. Fortunately, they stopped."
Tensions have spiked in recent months between Manila and Beijing over China's assertive activities within the Philippines' economic exclusion zone (EEZ).
Rodrigo Duterte, the Philippine president, warned last week that he would not withdraw his own coastguard and naval patrols, insisting the country's sovereignty over the waters is not negotiable. "I'll tell China, we do not want trouble, we do not want war. But if you tell us to leave - no," Duterte said. "There are things which are not really subject to a compromise, such as us pulling back."
Analysts have described the news team's unsettling encounter as an escalation of China's swagger in the resource-rich region, where it has already established a patchwork of military outposts on artificial islands. According to Philippine media reports, the Houbei attack craft were first spotted by a maritime patrol earlier this year at Mischief Reef in the east of the Spratlys, 130 nautical miles from Palawan, and where China has built a runway.
"It certainly speaks to the evolution of China's air and naval bases, especially the three big ones that they have out in the Spratlys," said Greg Poling, the director of the Asia Maritime Transparency Initiative at the Centre for Strategic and International Studies in Washington.
The missile boats appear to be a step up from the coastguard, naval and paramilitary boats normally harboured there. "What makes the Houbei class missile boats interesting is that they are really not meant to operate 800 miles from the Chinese coast so once they are out there, they are presumably going to stay," he said.
China's bases had moved "Chinese power projection capabilities 800 miles south" and would be used to squeeze out rival territorial claimants, said Poling. "It fundamentally changes China's ability to keep up a daily presence that is just grinding Philippine, Vietnamese and Malaysian defences down, and I think the Houbei classes are just another aspect of it," he said.
"Now they have got these fast patrol boats that can buzz out from Mischief Reef and razz the Filipinos whenever they do something that Beijing doesn't like, and if it's about numbers then China has now got more boats parked in the vicinity of the Philippines than the Philippines does."
In recent weeks, the V-shaped Whitsun Reef became a flashpoint after more than 200 Chinese vessels anchored there, defying diplomatic protests from Manila and the US amid accusations that China illegally built structures in the Union Banks, the series of reefs in the Spratlys that includes Whitsun.
China has denied all charges, insisting the boats anchored in the area to shelter from rough seas – an excuse that has failed to placate Philippine politicians, despite simultaneous offers from Beijing of Covid-19 vaccines.
"I think we are looking at a big Trojan horse here," said Senator Richard Gordon. "Our position is clear, we should be able to exercise our rights in our exclusive economic zone, we should not be intimidated, we should not be bamboozled by China's naked display of power."
Fuelling Philippine alarm is the likely presence of the People's Armed Forces Maritime Militia amid the fleet that swarmed the reef for weeks before spreading out around the area.
"A good number of them are fishing trawlers but they are very likely manned by maritime militia," said Collin Koh, a research fellow at the S Rajaratnam School of International Studies in Singapore, referring to China's tactic of arming and training fishermen to target anyone challenging its claims to the region.
The militia is increasingly deployed to conduct reconnaissance, supply garrisons, and use its sheer size to muscle South China Sea rivals out of disputed waters despite their rights under international law.
Supported by government subsidies, the militia has been built up over decades, but given China's "emphasis on maritime sovereignty, they now play an important, increasingly important role", said Koh. "The motto is 'nengyu nengzhan' which means: "can fish, can fight," he added.
"They do fall under military command and control … their activities even in peacetime are coordinated with the military," he said, but the blurring of lines between fishing and state-sponsored activities gave the Chinese "plausible deniability".
Euan Graham, a senior fellow at the International Institute for Strategic Studies, said the Whitsun Reef incident had been an "open poke in the eye to the Philippines".
But he warned that a much wider strategy was also at play that would be crucial to China's ambitions to take over the island of Taiwan, which it claims as its own.
"Taiwanese defence planners are increasingly worried about the vulnerability of the south line of approach for any aggression against Taiwan and that would, of course, come through the South China Sea and from those facilities that China is gradually thickening out and operating from," he said. "They are very much linked in operational terms."