WASHINGTON: US President-elect Joe Biden has held separate congratulatory phone calls with the leaders of Australia, Japan and South Korea, his transition office said on Wednesday. All sides expressed their determination to strengthen bilateral ties as well as tackle global issues such as the coronavirus pandemic and climate change, the office said. After defeating President Donald Trump last week, Biden has focused on laying the foundation of his administration, while the Republican incumbent Trump has been pressing ahead with his long-shot strategy to upend his election defeat with lawsuits.