Beijing: Warning of China's increasing military engagement in "unsafe and unprofessional behaviour" in the South China Sea, a US official said that such provocations risked a major incident in the region, media reports said.

Addressing a think tank's annual conference in Washington on July 26, Assistant Secretary of Defence for Indo-Pacific Security Affairs Ely Ratner said, "In recent months, we've witnessed a sharp increase in unsafe and unprofessional behaviour by PLA (People's Liberation Army) ships and aircraft, implicating not only US forces but allied forces operating in the region."

Ratner also criticized China for "dozens of dangerous events in the first half of this year alone." The US official was pointing toward the interception by the Chinese army in the lawful operations conducted by the US allies and partners in international airspace in the contested waters, reported Straits Times.

This is a key development as US President Joe Biden and Chinese President Xi Jinping are expected to speak in a call this week. In the backdrop is the rising tensions over Taiwan and the South China Sea.

The conference on the South China Sea was held by the Centre for Strategic and International Studies. He emphasized that the interception carried out by China was not an isolated incident and that such incidents have increased dramatically over the past five years.

"This aggressive and irresponsible behaviour represents one of the most significant threats to peace and stability in the region today, including in the South China Sea. If the PLA continues this pattern of behaviour, it is only a matter of time before there is a major incident or accident in the region," said Ratner.

An international arbitral tribunal's finding in 2016 noted that China's maritime claims in most of the South China Sea are unlawful. The finding also stressed Beijing holds freedom of navigation operations to boost its claims, which overlap with those of several Southeast Asian nations.

US backs all these findings fully. Washington argues that China's actions in the disputed waters undermine the international rules-based order.

Chinese Foreign Minister Wang Yi repeated the point on Monday, saying that the South China Sea was not a "fighting arena" for major powers to compete in.

In his address on Tuesday, Ratner gave an example of an incident reported by Australia's defence ministry early last month, of a Chinese J-16 fighter jet cutting across the nose of an Australian P-8 reconnaissance plane conducting routine overflight activities in the South China Sea.

Australia said that the Chinese manoeuvre was "very dangerous". As per Canberra, the Chinese jet released a round of chaff (a cloud of small pieces of aluminium aimed at confusing radar) which was ingested into the Australian P-8 plane's engine, as per the media portal.

In its defence, China levelled allegations on Australia saying that the country was "approaching Chinese airspace." Continuing the agenda Beijing said its forces issued warnings to dispel the Australian warplane in a "professional, safe, reasonable and legal" manner however they persisted.

Highlighting this chaff incidence, Ratner said there has been a series of unsafe intercepts of Canadian aircraft conducting UN Security Council resolution enforcement activities in the East China Sea last month, and another incident in February when a Chinese navy ship directed a laser at an Australian jet.

Beijing has denied both the Australian and Canadian accounts of the incidents and says its actions conformed to international law.

Earlier at the same event, US Deputy Assistant Secretary for Multilateral Affairs and for Global China issues Jung Pak also spoke on Beijing's "provocative actions" against its rival claimants and "other states lawfully operating in the region".

"There is a clear and upward trend of PRC provocations against South China Sea claimants and other states lawfully operating in the region," she said, using the People's Republic of China's official name.