- British Prime Minister Boris Johnson said he looked forward to working closely with the new US administration.
- "Europe has a friend in the White House," the European Union remarked.
- Joe Biden will be inaugurated on Wednesday, signaling the end of the Donald Trump presidency.
Several world leaders said they were looking forward to Wednesday's transfer of power in the United States, where Democrat Joe Biden will be sworn in as president after four turbulent years under Donald Trump.
Top EU officials voiced relief that they would soon have a friend in the White House again.
"Let's build a new founding pact for a stronger Europe, for a stronger America and for a better world," said Charles Michel, president of the European Council.
"This time-honoured ceremony on the steps of the US Capitol will be a demonstration of the resilience of American democracy," added European Commission President Ursula von der Leyen.
"And the resounding proof that, once again, after four long years, Europe has a friend in the White House."
President Hassan Rouhani did not miss the opportunity to hail the departure of "tyrant" Trump, with Tehran repeatedly calling on Washington to lift sanctions imposed over its nuclear drive.
Biden's administration wants the United States back in the landmark Iran nuclear accord which Trump withdrew from, conditional on Tehran's return to strict compliance.
A "tyrant's era came to an end and today is the final day of his ominous reign," Rouhani said.
"We expect (the Biden administration) to return to law and to commitments, and try in the next four years, if they can, to remove the stains of the past four years."
NATO said it hoped to boost transatlantic ties under Biden.
"We look forward to working with President-elect @JoeBiden to further strengthen ties between the #UnitedStates & #Europe, as we face global challenges none of us can tackle alone," the military alliance's chief Jens Stoltenberg wrote Tuesday.
Prime Minister Boris Johnson said he was looking forward to "working closely" with Biden.
Johnson, who has faced criticism over his close relationship with Trump, cited a host of policy areas in which he hoped to collaborate with Biden.
"In our fight against Covid and across climate change, defence, security and in promoting and defending democracy, our goals are the same and our nations will work hand in hand to achieve them," he said in a statement.
Former Soviet leader Mikhail Gorbachev called for Russia and the United States to repair their strained ties.
"The current condition of relations between Russia and the United States is of great concern," Gorbachev said in an interview with state-run news agency TASS.
"But this also means that something has to be done about it in order to normalise relations," he said.
"We cannot fence ourselves off from each other."