Japan and the US joined forces Tuesday to criticise China's “coercion and aggression" in Asia as senior ministers from both countries held their first in-person talks since President Joe Biden took office in January.

Aside from the sharp rhetoric aimed at Beijing, the meeting in Tokyo and a planned stop next in Seoul are as much an effort by the Biden administration to reassure worried allies in Asia after four years of occasionally confrontational dealings with the Trump administration.

US Secretary of State Antony Blinken, after holding the so-called “two plus two” security talks with Defence Secretary Lloyd Austin and their Japanese counterparts — Foreign Minister Toshimitsu Motegi and Defence Minister Nobuo Kishi — said democracy and human rights in the region are being challenged and the US will push with its partners for a free and open Indo-Pacific.

Blinken said the Biden administration is committed to work with US allies and those in the region as they face challenges from China and its ally North Korea, which is pursuing an illicit nuclear weapons program.

“We will push back if necessary, when China uses coercion or aggression to get its way,” he said.

In a joint statement released after the talks, the ministers also shared strong worry over Beijing's human rights violations in Xinjiang, “unlawful maritime claims and activities in the South China Sea” and “unilateral action that seeks to change the status quo” over the Japan-controlled East China Sea islands that China also claims. The statement also stressed the importance of “peace and stability” in the Taiwan Strait.

On the Biden administration's first Cabinet-level trip abroad, Blinken and Austin also agreed with their Japanese counterparts to cooperate on the coronavirus pandemic and climate change, as well as the nuclear threat posed by North Korea and the situation in Myanmar after its military coup.

On Tuesday, just as the two US officials arrived, North Korean leader Kim Jong Un's powerful sister warned the US to “refrain from causing a stink” if it wants to “sleep in peace” for the next four years. She also criticised the US and South Korea for holding military exercises.

Kim Yo Jong's statement Tuesday was North Korea's first comments directed at the Biden administration.

Biden's decision to send key ministers to Japan as their first overseas visit — rather than hosting Japanese officials in Washington — means a lot for Japan, which considers its alliance with the US the cornerstone of its diplomatic and security policies.

Blinken, in his opening remarks at an earlier meeting with Motegi, said “it is no accident that we chose Japan for the first Cabinet-level overseas travel" of the Biden administration, and that he and Austin are “here to reaffirm our commitment to the alliance and to build on it.” He said the US and its allies are working on together on climate change, cyber security and health security “in support of our shared values.”

Blinken also said that the US and Japan are expected to reaffirm the importance of their three-way partnership with South Korea and may touch on the strained relations between Tokyo and Seoul over wartime compensation issues.

South Korea and Japan have been struggling to repair relations that sank in 2019 following South Korean court rulings that ordered Japanese companies to pay reparations for forced labour during WW-II. Those rulings led to trade curbs by both countries and Seoul threatened to scrap a bilateral military intelligence-sharing agreement that was a major symbol of the countries' three-way security cooperation in the region.

Since then, Japan and US have changed leaders, leaving hope for improved relations.

Motegi, after the talks with Blinken, said the two ministers both oppose China's attempt to unilaterally change the status quo in the region's seas. The two ministers also agreed on the importance of complete denuclearization of North Korea, he said.

Japan is in a delicate diplomatic situation because its economy, like those of other countries in the region, heavily depends on China.

But Tokyo considers China's escalating maritime activity in the region a security threat. Beijing has built manmade islands in the South China Sea and equipped them with military equipment and is pressing its claim to virtually all of the sea's key fisheries and waterways. Japan is concerned about China's claim to the Japanese-controlled Senkaku Islands, called Diaoyu in China, in the East China Sea and its increased activity in the disputed area.

China has denied it is expansionist and has said it is only defending its territorial rights.

Later Tuesday, the American officials met with Japanese Prime Minister Yoshihide Suga, who is expected to visit Washington sometime in the first half of April to meet with Biden in person — becoming the first foreign leader to do so since Biden became president in January.

In a move meant to signal his intention for the US to more strongly engage with the Asia-Pacific region, Biden on Friday held a first virtual summit of the leaders from Australia, Japan, India and the US, a grouping known as the 'Quad', and emphasised Washington's commitment to the region.

Blinken and Austin on Wednesday will head to South Korea, with the focus of those talks being North Korea and its nuclear ambitions.

Blinken will meet senior Chinese officials in Anchorage, Alaska, on his way back to Washington. Austin will go from Seoul to New Delhi for meetings with Indian leaders.