SEOUL/TOKYO/WILMINGTON, Del. — In their first calls with Joe Biden since the US election, the leaders of Japan, South Korea and Australia on Thursday reaffirmed plans to form close ties with the president-elect to tackle issues including climate change and regional security.

The three key Asian allies — Japanese Prime Minister Yoshihide Suga, South Korean President Moon Jae-in and Australian Prime Minister Scott Morrison — join other global leaders in recognizing the Democratic challenger’s Nov. 3 victory over incumbent Donald Trump, who has so far refused to concede.

Mr. Biden’s projected win comes against a backdrop of China’s growing military and economic assertiveness in the region, and after years of sometimes tumultuous relations between Asian allies and the United States under Mr. Trump over issues including trade, defence and the environment.

All sides expressed their determination to strengthen bilateral ties as well as tackle global issues such as the coronavirus pandemic and climate change, Mr. Biden’s office said.

Japan’s Mr. Suga said he spoke with Mr. Biden by telephone and confirmed the importance of bilateral ties. “President-elect Mr. Biden said that he looks forward to strengthening the US-Japan alliance and working together on achieving a free and open Indo-Pacific,” Mr. Suga said to reporters, in separate comments made at the Prime Minister’s Office.

Many world leaders including United Kingdom, France and Germany as well as others have already congratulated Mr. Biden for his win, while China and Russia have so far held off.

Mr. Biden on Wednesday named Ron Klain as his White House chief of staff, his first major appointment as he builds his administration. Anthony Blinken, a diplomat and longtime confidant of Mr. Biden is seen as a likely pick for Secretary of State or National Security Adviser, both key roles for Asian allies.

Speaking to South Korea’s Mr. Moon, Mr. Biden reaffirmed the US commitment to defend South Korea, highlighting the Asian ally as a “lynchpin of the security and prosperity of the Indo-Pacific region,” Mr. Moon’s spokesman Kang Min-seok said.

“President Moon asked for close cooperation for the forward-looking development of the bilateral alliance, and the denuclearisation and peace on the Korean peninsula,” Mr. Kang told a briefing. “President-elect Biden said he would closely cooperate to resolve the North Korean nuclear issue.”

Mr. Trump and North Korean leader Kim Jong Un vowed to work towards denuclearisation at their unprecedented summit in 2018, but little progress has been made since their second summit and working-level talks collapsed last year. While Mr. Biden has said he would not meet with Kim without preconditions, he has also said he would embrace “principled diplomacy” with North Korea.

South Korean officials are also hopeful that Mr. Biden will quickly resolve a drawn-out, multi-billion dollar dispute with Washington over the cost of thousands of US troops on the peninsula.

Tackling the global coronavirus pandemic and climate change were key themes in Mr. Biden’s calls with all three leaders, readouts from Mr. Biden’s office showed.

Australia’s Mr. Morrison said he spoke with Mr. Biden about emission reduction technology, though a target for zero net emissions by 2050 was not discussed.

“I raised with the president-elect the similarity between the president-elect’s comments and policies regarding emissions reduction technologies that we needed to achieve that, and we look forward to working on those issues,” Mr. Morrison told reporters in Canberra.

Both Mr. Moon and Mr. Suga said they agreed to arrange summits with the new president shortly after his inauguration in January.

Mr. Biden will also face the challenge of managing unresolved political and economic disputes between South Korea and Japan, which have threatened a military intelligence-sharing arrangement and complicated US efforts to counter China. — Reuters