SINGAPORE - While 99 per cent of the United States Pacific Fleet's interactions with the Chinese navy are safe and professional, the remaining 1 per cent worries the fleet's commander, Admiral John Aquilino.

Responding to a question on whether incidents in the South China Sea he was worried about are on the rise, he said the No. 1 priority for the fleet is force protection, adherence to the International Regulations for Preventing Collisions at Sea (COLREGS), as well as operating safely on the sea.

"We do use Cues, which was a negotiation previously with China on how to avoid potential miscalculations at sea, so we will continue to operate by those rules, but I'm always worried about the 1 per cent," said Admiral Aquilino on Friday (Oct 25), adding that the 1 per cent refers to near-mishaps.

The US navy has been conducting "freedom of navigation" operations in recent years to challenge China's territorial claims in the disputed South China Sea. Besides Taiwan, four Asean nations also make overlapping claims over the vital waterway.

Encounters between American and Chinese naval ships and military aircraft - including two destroyers USS Decatur and Lanzhou coming within 41m of a collision in September 2018 - have sparked fears of conflict in the region.

Admiral Aquilino, who is in Singapore for his introductory visit from Thursday (Oct 24) to Saturday, met Defence Minister Ng Eng Hen and Chief of Defence Force, Lieutenant-General Melvyn Ong, at the Ministry of Defence (Mindef).

In a statement, Mindef said Admiral Aquilino and Dr Ng reaffirmed the strategic partnership and strong defence ties between Singapore and the United States during their meeting.

They also reaffirmed the substantial and wide-ranging areas of cooperation between the Singapore navy and the US Pacific Fleet.

Admiral Aquilino, speaking on Friday during a 20-minute interview at the US Embassy in Napier Road, took questions ranging from China's activities in the South China Sea, to denuclearisation in the Korean peninsular and the recently-concluded inaugural Asean-US Maritime Exercise.

Asked about Chinese weapons systems that were on display during the anniversary parade to mark 70 years since the founding of the People's Republic of China, which some analysts have said could be a threat to the US, the admiral said: "What I would say is that the display put up by China confirms to me that the region is a contested environment."

However, the US navy will continue to sail and fly anywhere international law allows. The linkage of the sea and nations operating in accordance with international law has been the foundation for prosperity in the region over the past seven decades, said Admiral Aquilino, who took over command in May last year.

"So no matter what we see involved in those types of events, it's important for the nations in the area to have a common voice, to enjoy their sovereignty, to not get bullied, and to continue the international rules-based norm that have gone on in the region since WWII," he added.

The US Pacific Fleet's area of responsibility covers nearly half the Earth's surface, from the west coast of the United States to the Indian Ocean.

There are about 200 ship and submarines, nearly 1,200 aircraft, and more than 130,000 sailors and civilians under its charge.

The admiral said he was confident that the code of conduct being drafted by China and Asean countries to manage territorial disputes in the South China Sea by 2021 will reflect current interpretations of international law and UNCLOS (United Nations Convention on the Law of the Sea).

"If that happens, then it would be a worthwhile document. If it were to come out in opposition to interpretations of international law, that would be a concern."

On the first Asean-US Maritime Exercise, which involved eight warships and four aircraft from seven countries last month, Admiral Aquilino said it was "very impressive" for all the countries in the region to come together to iron out the specifics of the exercise, such as the participation and where it would be held.

"So I was really happy with the first event, and we hope to do more in the future," he said, adding that a date for the next such exercise has not been fixed yet.