The pope called on Trump to be guided by the 'rich spiritual and ethical values' that have shaped US history

The pope has called on Donald Trump to be guided by the 'rich spiritual and ethical values' that have shaped US history as he takes office.

He is one of many world leaders reacting to the inauguration of Republican Trump as the 45th President of the USA.

While many leaders have sent messages of congratulations to Trump, Germany's Vice Chancellor has warned of a 'rough ride' ahead and said his election is the result of 'bad radicalisation'.

In a personal message to the new head of state, Pope Francis said: 'Under your leadership, may America's stature continue to be measured above all by its concern for the poor, the outcast and those in need.'

Israeli Prime Minister Benjamin Netanyahu has branded Trump a 'friend' and said he is looking forward to 'working closely with you to make the alliance between Israel&USA stronger than ever'.

Netanyahu has been briefed, Israeli newspaper Haaretz reports, by security services on the potential for Palestinian violence if Trump follows through on his promise to move the US embassy from Tel Aviv to Jerusalem.

Israeli Prime Minister Benjamin Netanyahu (left) has branded Trump a 'friend', while Japanese Prime Minister Shinzo Abe said he intends to meet the new US President 'at the earliest possible occasion'

The prime minister of Japan - one of America's closest allies - congratulated Trump and said he wants to strengthen the 'unwavering' ties between the two nations.

In a statement issued minutes after Trump took the oath of office, Shinzo Abe said he looks forward to meeting Trump again 'at the earliest possible occasion'.

Reports in Japan state that Abe may visit the US in late January.

World leaders have sent messages of congratulations to Donald Trump after his inauguration as President of the USA

Mexican President Enrique Peña Nieto (pictured with Trump in August last year) said the two countries should 'work to strengthen our relationship'

Mexican President Enrique Peña Nieto tweeted his congratulations to Trump.

He wrote in Spanish: 'I congratulate President @realDonaldTrump in taking office. We will work to strengthen our relationship with shared responsibility.'

But former President Vicente Fox was scathing about the new US head of state, tweeting: 'Speaking of allegiance, Trump? Speaking of greatness? Speaking of success? America was already great and succesful [sic], then you happened!'

Trump's election victory has sparked security concerns in eastern Europe, where officials fear his pro-Russian views could hurt the region's interests.

Canadian Prime Minister Justin Trudeau issued a statement welcoming Trump to office

In a statement Canadian Prime Minister Justin Trudeau said: 'Together, we benefit from robust trade and investment ties, and integrated economies, that support millions of Canadian and American jobs.

'We both want to build economies where the middle class, and those working hard to join it, have a fair shot at success.'

And he added: 'We look forward to working with President Trump, the US Administration, the 115th Congress, and officials at the state and local levels to restore prosperity to the middle class on both sides of the border, and to create a safer and more peaceful world.'

German Chancellor Angela Merkel was at an art gallery in Potsdam during the inauguration ceremony

Instead of watching the inauguration, German Chancellor Angela Merkel visited an art gallery in Potsdam.

In the hours after Trump's inauguration, Vice Chancellor Sigmar Gabriel warned against protectionism and said Germany would have to brace itself if the US starts a trade war with China.

He told public broadcaster ZDF: 'I think we have to prepare for a rough ride.'

Gabriel added that Trump's election was the result of 'a bad radicalisation'.

Merkel has not spoken publicly about Trump today, but after his November election win, she said relations between the two countries would only work if he upheld 'the dignity of man, independent of origin'.

Russian President Vladimir Putin, pictured the day of Trump's election win in November, was one of the first world leaders to congratulate Trump on his win

Celebrations were held in Moscow to mark Trump's inauguration as President of the USA

In Russia, celebrations have been held to mark Trump's inauguration.

Russian nationalists held an all-night party at what used to be the main Soviet-era post office in Moscow.

To the east, in the city of Zlatoust, craftsmen released a limited series of silver and gold commemorative coins, engraved with 'In Trump We Trust'.

After Trump's election win, Putin called for relations between the two superpowers - which had been strained during the Obama regime - to be rebuilt.

News agency Interfax reported that the Russian Parliament burst into applause after Trump’s victory was confirmed.

Putin was later pictured sipping on a glass of champagne at a meeting for foreign ambassadors in Moscow.

Indian Prime Minister Narendra Modi offered his best wishes to Trump

In a speech in the Kremlin, Putin stated: 'We have heard the pre-election statements by then-candidate (Trump), which were directed at rebuilding relations between Russia and the US.

'We understand that this will not be an easy path considering the unfortunate degradation of relations.

'But Russia is ready and wants to restore full-fledged relations with the US.'

Indian Prime Minister Narendra Modi enthusiastically welcomed the new US President, writing on Twitter: 'Best wishes in leading USA to greater achievements in the coming years.'

Foreign minister Witold Waszczykowski said Poland felt neglected by former President Barack Obama in the early years of his administration.

Trump has caused unease in Central and Eastern Europe nations that he might sacrifice their security needs at a time they are especially fearful of Russia.

Linas Linkevicius, foreign minister in Lithuania, said some of Trump's statements have been 'confusing', but he said he is not jumping to any conclusions.

Earlier this week Chinese President Xi Jinping invoked the Gettysburg Address to take aim at Trump's trade plans.

Speaking at the World Economic Forum in Davos, Switzerland, he said economic development is 'of the people, by the people and for the people,' quoting the iconic Abraham Lincoln speech.

President Xi also spoke against protectionism which lies at the heart of President-elect Trump's trade policies.

'No one will emerge as a winner in a trade war,' he said in his speech at the economic event.

Palestinian President Mahmoud Abbas has congratulated Trump as he takes office

Palestinian President Mahmoud Abbas, in a statement posted in his name on the official Palestinian news agency WAFA, congratulated Trump.

He added: 'I look forward to working with him for the sake of peace, security and stability in a world that is troubled and in a region that lives a tragic era, and to contribute to creating a safe future for everyone.'

Former NATO chief Anders Fogh Rasmussen, now an adviser to Ukranian President Petro Poroshenko, said in a telephone interview with Reuters: 'I had hoped and also expected a more internationally oriented speech. Instead we got a very domestically oriented, anti-establishment speech.

'As president of the United States, he should also realize he has become the leader of the free world - that's why people all over the globe are watching his inauguration speech. And that's why I had hoped that he would also address the need for determined American global leadership.'

French President Francois Hollande has yet to address Trump's inauguration. After the Republican's election win in November, Hollande gave a lukewarm response, saying it heralded a period of 'uncertainty'.

He said: 'I congratulate him as is natural between two democratic heads of state. This American election opens a period of uncertainty.'

He said France would be vigilant and frank in talks with the new White House administration.