Opposition parties said Sunday they are closely monitoring possible changes in America's foreign policy that could be brought by Joe Biden, a Democrat elected to be the next U.S. president.

Referring to Japan's engagements with neighbors and global issues such as the novel coronavirus pandemic, Yukio Edano, head of the Constitutional Democratic Party of Japan, said Biden's victory over Republican President Donald Trump in Tuesday's election will force a shift in U.S. relations with Russia, North Korea and other countries.

"It is the job of politics to maximize Japan's national interest in such situations," Edano said in a speech at Tokyo's Waseda University, urging Prime Minister Yoshihide Suga to build sound ties with the president-elect, especially as Tokyo tries to resolve territorial disputes with Moscow and abduction issues with Pyongyang.

Japanese Communist Party chief Kazuo Shii said in a statement that he is paying close attention to what kind of policy measures Biden will pursue on the Paris agreement and the coronavirus pandemic through the World Health Organization.

Trump effectively withdrew the United States from the 2015 U.N. accord to fight climate change and the WHO. Biden, however, has pledged that the United States will rejoin the accord and will remain a WHO member.

Yuichiro Tamaki, leader of the Democratic Party for the People, said in a Twitter post that he will closely watch how a new U.S. administration will deal with China and the pandemic.

Tadatomo Yoshida, secretary-general of the Social Democratic Party, said he hopes societal divisions he says were deepened by the Trump administration will be repaired.