Over the past months, as countries in the Pacific region were focused on battling the coronavirus, multiple sources reported that China stepped up patrols and naval exercises in the highly disputed South China Sea.

Read more: South China Sea - what you need to know

The activities of the Asian powerhouse in the region, however, did not slip by the eyes of Washington, which went on to accuse Beijing of "exploiting" its neighboring countries as they are "distracted" with the pandemic.

"We call on the PRC [People's Republic of China] to remain focused on supporting international efforts to combat the global pandemic and to stop exploiting the distraction or vulnerability of other states to expand its unlawful claims in the South China Sea," the US Department of State said in a statement in early April.

The accusation resurfaced over the weekend at a press conference during China's legislative meetings in Beijing where China denied the allegations. "There is nothing to support the claim that China is using COVID-19 to expand its presence in the South China Sea," said Chinese Foreign Minister Wang Yi.

Wang stated that China was working to support neighboring countries in their efforts against the virus and criticized the US for "politicizing" China's actions as well as for "foreign meddling" in Hong Kong with regards to China's proposal for imposing a new security legislation.

Longstanding tensions between the administrations of US President Donald Trump and Chinese President Xi Jinping also worsened in recent weeks over the origins of the coronavirus pandemic.

"It has come to our attention that some political forces in the US are taking China-US relations hostage and pushing our two countries to the brink of a new Cold War," Wang told reporters on Sunday. The top Chinese diplomat did not identify the "forces" to which he was referring.

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US-China rivalry

China, Brunei, Vietnam, the Philippines, Malaysia and Taiwan have overlapping claims to the South China Sea - one of the most important trade routes in the world.

Powerhouse China has the biggest claim by far. It has demarcated an extensive area of the sea with a so-called "nine-dash line" that first appeared on Chinese maps in the late 1940s. The Paracel and Spratly Island chains, as well as dozens of rocky outcrops and reefs, fall within this area. These bits of land are highly contested, mainly because they are believed to be surrounded by large oil and gas deposits.

The Spratly Islands, for example, are claimed in full by China, Taiwan, and Vietnam, and in part by Malaysia and the Philippines. The Paracel chain is claimed by Vietnam, China and Taiwan.

Some analysists think that China's claim to the South China Sea – the so-called "nine-dash line" – should be considered unlawful and a breach of international conventions.

In response to Beijing's growing presence in the South China Sea, the US has also continued its naval presence in the area.

The US nuclear powered aircraft carrier – the USS Theodore Roosevelt – was forced to depart from the South China Sea in March and dock in Guam due to an outbreak of COVID-19. The carrier is now seen patrolling the Philippines Sea and will most likely head back to the South China Sea.

For years, the US has been conducting the so-called Freedom of Navigation Operations in the sea in what Washington considers to be a defense strategy against potential threats to commercial shipping and alleged bullying from China against rival claimants like Malaysia and Taiwan.

In April, a Chinese vessel allegedly rammed and sank a Vietnamese fishing boat, resulting in a diplomatic spat between the two countries. Vietnam was joined by the Philippines in denouncing the incident. China then declared two archipelagos in the South China Sea as administrative districts, which Vietnam's foreign ministry said was a violation of the country's sovereignty.

Read more: How Asia's official maps promote propaganda

'Business as usual'

Despite accusations from the Trump administration, there has been some disagreement as to whether China has become increasingly aggressive in its activities in the sea or whether they simply form a part of Beijing's long-term strategy.

"I disagree with Trump Administration officials that China has become more assertive or aggressive in the South China Sea by taking advantage of the COVID-19 pandemic," said Carl Thayer, an emeritus professor at Australia's University of New South Wales. "If you look at last year and this year, China is conducting 'business-as-usual.'"

According to Thayer, Beijing's aggressive actions in the South China Sea reflects its needs not to be perceived as weak by China’s domestic audience and foreign public opinion. China is also driven by the necessity to react to perceived challenges to its sovereignty, for example US navy patrols in the region and oil explorations by Vietnam and Malaysia.

Peter Dutton, a professor at the US Naval War College in Rhode Island, agreed that China's recent activities are not escalations but most likely are reactions to political developments in the region. This includes last week's re-election and subsequent inauguration of Taiwan's President Tsai Ing-wen (LINK) in addition to the White House's growing support for Taiwan. Tsai Ing-wen has called for a more independent identity for the island nation despite China's insistence that Taiwan is a breakaway province.

"I think a lot of what you're seeing can be attributed to that, even in the South China Sea," said Dutton. "The larger political dynamic in the region from China's perspective still has to do very much with the power dynamics in relation to Taiwan."

Read more: US-ASEAN naval drills kick off in Southeast Asia

US allies drawn into 'war of words'

Australia joined in on the US-China row after deciding to support Washington with an inquiry into China's role in the coronavirus outbreak and the World Health Organization's (WHO) response to the pandemic. In retaliation, China imposed tariffs of up to 80% on barley imports from Australia. Earlier in April, Australia also took part in a South China Sea naval exercise with the US.

Growing tension between Canberra and Beijing has long concerned Australian officials as the country's economy is highly dependent on Chinese customers and on having access to the shipping channels that traverse the region, Thayer explained.

"China's increased diplomatic influence, economic heft and military power in the Indo-Pacific Region and the South Pacific is a major concern, particularly as China is Australia’s major trading partner," Thayer said.

Dutton also acknowledged that the interplay between politics, economics and security is a reality for all countries that border the South China Sea, as well as for those whose economies depend on its shipping channels – leading them to remain engaged at a military level.

"There's a balance of power, say, between China and Taiwan or between China and Japan. When that balance shifts in China's favor, that produces tension, instability, risk and so on," said Dutton. "The US, Japan, Australia and others have an interest in trying to stabilize that power balance a little bit more in order to ensure regional stability."

Read more: Did China commit 'crimes against humanity' in the South China Sea?