But reports are that China has installed missile defence systems - on recently constructed islands in the South China Sea - prompting heavy criticism from anti-Duterte factions of the country, citing the president's inaction in response to the undertaking.
"When they (Chinese) do things that are opaque to the rest of us, then we can not cooperate in areas that we would otherwise cooperate in", Mattis told reporters, adding that American diplomats were working on the issue and heard concerns about Chinese actions not just from the USA government but other regional allies as well. "And we have been reporting to you and the public", he added.
This bomber, China's most advanced, has conducted take-off and landing training, the channel said.
He said the government was merely looking for a "proper time" to take "full advantage" of the arbitral ruling.
Amid accusations that the Philippines was not taking advantage of an arbitral ruling that upheld Philippine sovereign rights over disputed territories in the West Philippine Sea, Esperon said, "This Administration does not and will not abandon the ruling of the Permanent Court of Arbitration on the South China Sea disputes".
The United States will continue to conduct military exercises in the South China Sea despite rising tensions with Beijing, US Defense Secretary James Mattis told reporters.
Esperon said the Philippines is building five lighthouses on the Kalayaan Group of Islands, a feature of Spratlys in the West Philippine Sea which is claimed by Manila, according to ABS-CBN News.
Philippines island construction: the island nation itself "has started repairing a runway and upgrading other facilities on Thitu Island, the South China Sea territory that was a year ago the scene of a stand-off between Chinese and Philippine vessels", according to the South China Morning Post.
Mattis's remarks came after Beijing voiced "strong dissatisfaction" Sunday after two USA warships sailed by an island in the disputed Paracel Island chain.
Roseanne Barr blames Ambien for tweet; drug maker replies
Ellis went on to explain that comparing black people to apes goes straight to the heart of dehumanizing someone. But much of its progress would have been threatened if it looked the other way at Barr's tweet.
Reuters first reported that two U.S. Navy warships sailed near South China Sea islands claimed by China on Sunday, prompting anger in Beijing, which claims most of the strategic waters where Chinese, Japanese and some Southeast Asian navies operate.
Mattis says the United States will confront "what we believe is out of step with worldwide law". The officials have also expressed their concerns about how China is using the South China Sea islands as a haven to collect intelligence. "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.
"Our diplomats are robustly engaged on this", Mattis said.
The Pentagon, as it nearly always does, says the sailings were planned months in advance and that the timing in relation to recent tensions between China and the United States is coincidental.
Mattis is expected to have strong words for China when he travels to Singapore for the Shangri-la dialogue, a security forum, later this week.
Mattis was heading to Hawaii to attend a change-of-command ceremony for the USA military's Pacific Command.
U.S. Navy Adm. Philip Davidson will take over PACOM from Adm. Harry Harris during the change of command on Wednesday.
The current head, Admiral Harry Harris, has been nominated to be the new ambassador to South Korea.