One of the two officials, who spoke on condition of anonymity because they were not authorized to discuss the incident publicly, said the Philippines and China recently held talks to prevent a repeat of the incident, which earned the "displeasure" of the Philippine president.
"Yes, we have differences with them (China), but we have made gains".
He said he had assurances from Beijing that the missiles deployed at Fiery Cross (Kalayaan), Subi and Mischief reefs are aimed at China's potential enemies and not at the Philippines.
The United States is not daunted by Beijing's confrontation in its recent operation in the disputed South China Sea where the latter claims ownership.
On Tuesday, the US Secretary of Defense James Mattis said that the Trump administration would continue to confront what the United States sees as a militarization of the South China Sea islands. China denied the court ruling and argued that the tribunal had no jurisdiction in the case.
Cayetano said China has assured that the deployment of missiles in three reefs claimed by the Philippines as well as the testing and landing of Chinese bombers in Woody Island in the Paracels is "purely for defensive objective and not directed against the Philippines".
Mattis said American ships are maintaining a "steady drumbeat" of naval operations around the disputed islands, adding that "only one country" seems to be bothered by the vessels' routine activities.
Cayetano's speech came as the US Navy sailed two warships within 12 nautical miles of China's artificial islands in the Paracels, as part of their freedom of navigation exercises in the contested waters. "That's the way we do business in the world, but we're also going to confront what we believe is out of step with global law, out of step with worldwide tribunals that have spoken on the issue", he said. The operation that was conducted on Sunday had been undergoing drills and planning for months on end. "If there's multiple nation militarizing, and it isn't exclusively the islands, if big navies are crusing by means of the world, is that not militarization?" he mentioned.
The U.S. military does not comment on the specifics of what it calls "freedom of navigation" exercises meant to assert the Navy's right to sail and operate in any zone deemed legal under worldwide law.
The announcement underscores the continued deterioration in U.S.
"Our diplomats are robustly engaged on this", Mattis said.
China is facing increasing tension with the USA and its neighbours over the South China Sea issue.
Mattis was heading to Hawaii to attend a change-of-command ceremony for the US military's Pacific Command.
"It's clear that Xi wanted to follow up that last event to showcase his control over the Chinese People's Liberation Army (PLA), including his promise and call for the PLA to heighten combat readiness in the South China Sea", Dr Collin Koh Swee Lean of the S. Rajaratnam School of International Studies (RSIS), Singapore, told VnExpress.
The current head, Admiral Harry Harris, has been nominated to be the new ambassador to South Korea.
U.S. Navy Adm. Philip Davidson will take over PACOM from Adm. Harry Harris during the change of command on Wednesday.