By Angus MacSwan
LONDON (Reuters) - World leaders reacted to Donald Trump's victory in the U.S. presidential election with offers to work with him tinged with anxiety over how he would deal with a host of problems, from the Middle East to an assertive Russia.
Several authoritarian and right-wing leaders commended the billionaire businessman and reality TV star who against the odds won the leadership of the world's most powerful country.
Trump, who has no previous political or military experience, sent conciliatory signals after his upset of Democratic rival Hillary Clinton, pledging to seek common ground, not conflict, with the United States' allies.
During his election campaign, Trump expressed admiration for Russian President Vladimir Putin, questioned central tenets of the NATO military alliance and suggested Japan and South Korea should develop nuclear weapons to shoulder their own defense burden.
Putin was among the first to send congratulations after Trump declared victory.
Ties between Washington and Moscow have become strained over the conflicts in Ukraine and Syria, and allegations of Russian cyber attacks featured in the U.S. election campaign.
"We heard the campaign statements of the future U.S.
presidential candidate about the restoration of relations
between Russia and the United States," Putin said.
"It is not an easy path, but we are ready to do our part and
do everything to return Russian and American relations to a
stable path of development."
Among other issues causing concern among allies are Trump's vows to undo a global agreement on climate change, ditch trade deals he says have been bad for U.S. workers and renegotiate the nuclear accord between Tehran and world powers which has led to an easing of sanctions on Iran.
Iranian Foreign Minister Javad Zarif urged Trump to stay committed to the Iran deal. Iranian President Hassan Rouhani said the election result would have no effect on Tehran's policies and the nuclear accord with six world powers could not be dismissed by one government.
Elsewhere in the Middle East, Israel's Benjamin Netanyahu, who had a poor relationship with President Barack Obama, said he hoped to reach "new heights" in bilateral ties under Trump.
Obama and Netanyahu sparred over the issue of Israeli settlements, while Trump has said they should expand.
Palestinian President Mahmoud Abbas also congratulated Trump, but analysts said his rule may be profoundly negative for Palestinian aspirations.
And despite Trump's negative rhetoric about Muslims during his campaign, including threats to ban them from the United States, Egyptian President Abdel Fattah al-Sisi said he hoped the business magnate's election would breathe new life into U.S.-Egyptian ties.
In Britain, where Trump's victory had echoes of last June's referendum in which voters showed dissatisfaction with the political establishment by voting to leave European Union, Prime Minister Theresa May said the "enduring and special relationship" between the two countries would remain intact.
Nigel Farage, a leader of the Brexit campaign who spoke at a Trump rally during the election campaign, tweeted: "I hand over the mantle to @RealDonaldTrump! Many congratulations. You have fought a brave campaign."
But some European officials took the unusual step of denouncing the outcome, calling it a worrying signal for liberal democracy and tolerance in the world.
"Trump is the pioneer of a new authoritarian and chauvinist international movement. He is also a warning for us," German Vice Chancellor Sigmar Gabriel told Funke newspaper group.
Some leaders are smarting from insults that Trump doled out in the past few months, such as calling German Chancellor Angela Merkel "insane" for allowing more than 1 million migrants into the country last year.
"We're realizing now that we have no idea what this American president will do," Norbert Roettgen, a conservative ally of Merkel and head of the German parliament's foreign affairs committee, told German radio. "Geopolitically we are in a very uncertain situation."
President Francois Hollande said France wanted to begin talks with Trump immediately to clarify his stance on international affairs.
"This American election opens a period of uncertainty," Hollande said.
French officials had openly endorsed Clinton and warned that Trump's "confused" foreign policy objectives were alarming for the rest of the world.
"The U.S. is a vital partner for France and what's at stake
is peace, the fight against terrorism, the situation in the
Middle East, economic relations and the preservation of the
planet," Hollande said.
But like-minded right-wing European parties that are hoping to make inroads of their own in 2017 -- a year in which Germany, France and the Netherlands hold elections, and Italy and Britain could also do so -- hailed Trump's victory.
"Their world is falling apart. Ours is being built," Florian Philippot, a senior figure in France's far-right National Front (FN), tweeted.
In Asia, Chinese President Xi Jinping sent a message with a conciliatory tone, telling Trump that Beijing and Washington shared responsibility for promoting global development and prosperity.
"I place great importance on the China-U.S. relationship,
and look forward to working with you to uphold the principles of
non-conflict, non-confrontation, mutual respect and win-win
cooperation," Xi told Trump, who said on the campaign trail to take on China and to tax Chinese imports to stop currency devaluation.
South Korea expressed the hope that Trump would maintain current U.S. policy of pressuring North Korea over its nuclear and missile tests. Seoul was concerned Trump may make unpredictable proposals to North Korea, a ruling party official said, quoting top national security officials.
A Japanese government official, speaking before Trump clinched the election, urged him to send a message as soon as possible to reassure the world of the United States' commitment to its allies.
"We are certainly concerned about the comments (Trump) has made to date about the alliance and the U.S. role in the Pacific, particularly Japan," the Japanese official said.
(Reporting by Reuters bureaus in Europe, Asia and the Americas, Editing by Sonya Hepinstall and Angus MacSwan)