World leaders are seeking out phone conferences with US President-elect Joe Biden ahead of his inauguration, as sitting president Donald Trump still refuses to concede the election.
German Chancellor Angela Merkel and Mr Biden stressed the importance of transatlantic cooperation in their phone call on Tuesday after the Democrat's election victory, her spokesman said in a statement.
Congratulating Mr Biden, Ms Merkel "voiced her wish for a close and trustworthy cooperation," Steffen Seibert said.

German Chancellor Angela Merkel shakes hands with then-US Vice President Joe Biden in 2013. Source: DPA
"The chancellor and the president-elect were in agreement that transatlantic cooperation is of great importance given the numerous global challenges," he added.
French President Emmanuel Macron also held his first telephone talks with Mr Biden since his election, his Elysee Palace office said.
The talks between Mr Biden and Mr Macron, who also sought to form a solid working relationship with Mr Trump, focused on international cooperation on the main global issues, it added.
"The president congratulated Joe Biden and his vice president Kamala Harris and emphasised his desire to work together on the current issues - climate, health, the fight against terrorism and the defence of fundamental rights," the Elysee said.

French President Emmanuel Macron speaks on the telephone to US President-elect Joe Biden. Source: EPA
Mr Macron has never met Mr Biden, who served as vice president under Barack Obama from 2008-2016 before Mr Macron arrived at the Elysee in 2017.
In contrast to some other EU leaders, Mr Macron sought from the outset to build a strong relationship with Mr Trump, hosting him for a high profile visit to Paris in 2017 and then again for the 2019 G7 summit in Biarritz.
But analysts say that the French leader has little to show for the diplomacy, with vast differences between Paris and Washington on issues ranging from Iran to the taxation of digital giants.
The leaders of Britain and Ireland also spoke to Mr Biden, talking climate change and Brexit in a rush of calls with the president-elect reflecting key policy priorities.

French President Emmanuel Macron and US President Donald Trump embrace during last year's G7 summit. Source: ABACA
British Prime Minister Boris Johnson and his Irish counterpart Micheal Martin were among the first world leaders to talk to the incoming president after his election victory.
Downing Street said Mr Johnson had a 20-minute phone call with the Democrat, in which he also described vice-president-elect Kamala Harris' win as a "historic achievement".
"I look forward to strengthening the partnership between our countries and to working with him on our shared priorities – from tackling climate change, to promoting democracy and building back better from the pandemic," Mr Johnson wrote on Twitter.
They also discussed areas "such as trade and security - including through NATO", he added.
Mr Johnson said he was also looking forward to seeing Mr Biden when Britain takes over the rotating presidency of the G7 next year and invited him to attend the UN's COP26 climate change summit.
The summit had been due to be held this week in the Scottish city of Glasgow but has been postponed to next November because of the coronavirus pandemic.
'Shapeshifting creep'
London is hoping work to tackle climate change can thaw frosty relations between Mr Johnson and Mr Biden's camp, which have been strained over Brexit and the prime minister's past comments.
Mr Biden, who has strong Irish roots, has spoken out at a British plan to override parts of the Brexit treaty it signed that Democrats fear could undermine peace in Northern Ireland.
Irish prime minister Micheal Martin called his call "warm and engaging".

Ireland's Prime Minister Micheal Martin. Source: AFP
His office said Biden "reaffirmed his full support for the Good Friday Agreement", which ended three decades of violence over British rule in Northern Ireland.
"They discussed the importance of a Brexit outcome that respects the GFA and ensures no return of a border on the island of Ireland" - a key part of the 1998 peace accord.
Mr Biden and top Democrats have warned that Mr Johnson can effectively forget about a UK-US trade deal if Brexit scuppers the hard-won peace brokered by the United States.
His relationship with Mr Johnson will be closely watched, after he called the populist UK prime minister a "physical and emotional clone" of President Donald Trump last year.
Mr Biden was also vice-president in 2016 when Mr Johnson said then-president Barack Obama was anti-UK because of his "part-Kenyan" heritage and "ancestral dislike of the British Empire".
Former Obama aide Tommy Vietor was critical of Mr Johnson's congratulations to Mr Biden after his victory was announced on Sunday.
"This shapeshifting creep weighs in," Mr Vietor tweeted. "We will never forget your racist comments about Obama and slavish devotion to Trump but neat Instagram graphic."
But in policy terms, Britain is still far more aligned with Mr Biden and European allies on issues such as climate change, Iran, Russia and NATO defence.
The British government earlier blamed a "technical error" after Mr Trump's faded-out name appeared in the congratulatory written statement to Mr Biden that was posted online Sunday.
"As you'd expect, two statements were prepared in advance for the outcome of this closely contested election," said a spokesman.
"A technical error meant that parts of the alternative message were embedded in the background of the graphic."
Transition process blocked
The formal process of Mr Biden's transition is being blocked by Mr Trump while he attempts to overturn the election results in court on the basis of so far flimsy fraud allegations.
"WE WILL WIN!" the Republican president tweeted early Tuesday. "WATCH FOR MASSIVE BALLOT COUNTING ABUSE."
Mr Trump's attempt to hold on to power has become all-consuming for the man who often makes a point of publicly mocking rivals as "losers."
Emphasising the atmosphere of intransigence, Secretary of State Mike Pompeo said in a testy news conference that he was preparing for "a smooth transition to a second Trump administration."
Exactly four years ago on Tuesday, Mr Trump had just scored his surprise victory against Hillary Clinton and toured the White House for the first time as a guest of Barack Obama.
That courtesy to a president-elect is an old tradition, highlighting the nation's near-sacred respect for the peaceful transfer of power.
Mr Trump has not only failed to invite Mr Biden for a chat in the Oval Office, he is blocking the Democrat from access to facilities, funding and expertise that usually come in a ready made package to help the incoming leader.
Release of this transition aid is controlled by the General Services Administration head Emily Murphy, who was appointed by Mr Trump.

Donald Trump looks at supporters as he departs after playing golf at the Trump National Golf Club in Sterling Virginia, Sunday, 8 November. Source: AAP
On Monday, the Republican leader in Congress, Senator Mitch McConnell, said Mr Trump was "100 percent within his rights" to challenge the election in court.
None of the lawsuits appears to have the potential to change the result of votes and even a planned recount of Mr Biden's paper-thin victory in Georgia, or anywhere else, would be unlikely to change the fundamental math.
But Mr Trump added a potential new weapon to his crusade against the results on Monday when his attorney general, Bill Barr, agreed to authorise probes into "specific allegations" of fraud.
Mr Barr added a caveat that "specious, speculative, fanciful or far-fetched claims should not be a basis for initiating federal inquiries."
However, Mr Barr's unusual intervention in the dispute prompted worries that Mr Trump will go even further in his efforts. The Justice Department's top election crimes prosecutor, Richard Pilger, resigned in protest.