As millions of people watch Barack Obama's swearing-in ceremony, statesmen from around the world have been giving their reaction to the historic inauguration. Here is a selection of their comments:
I sincerely hope that President Obama will make as a matter of priority these Middle Eastern policies. As a member of the Quartet, as the leader of the world, the United States has full responsibility to lead this peace process so that this two-state solution, Israel, Palestinians can live in peace and security side by side.
Secretary-General Ban Ki-moon
The whole world is watching the inauguration of President Obama, witnessing a new chapter in both American history and the world's history.
Prime Minister Gordon Brown
He's not only the first black American president but he sets out with the determination to solve the world's problems.
We are eager for him to get to work so that with him we can change the world.
President Nicolas Sarkozy
We are ready for this. Our president confirmed this in a telephone conversation with Barack Obama straight after he was elected. I think there will be additional telephone - and not only telephone - contacts between our leaders.
Foreign Minister Sergei Lavrov
I want to say that I believe today is a very special day not only for the United States of America but also a special day for billions of people all over the world.
Chancellor Angela Merkel
The fact that a coloured president is being inaugurated and the fact the we a looking at an intensive transatlantic co-operation is something that not only moves the heads and thoughts but also the hearts. And I want to wish the new American President Barack Obama all the best, much strength and health and God's blessing .
And I want to say that Germany is prepared to liaise with him very intensely and very openly.
Obama gives us hope and his words put us on a better path for a smooth and fruitful relationship with the Spanish government. The arrival of Obama gives us an opportunity we won't pass up.
Prime Minister Jose Luis Rodriguez Zapatero
Many hopes and expectations have been piled on him, not just by the American people but also the rest of the world. The thing to do is to send him the most affectionate and cordial wishes so that he can fulfil these expectations.
Prime Minister Silvio Berlusconi
I pray that you will be confirmed in your resolve to promote understanding, co-operation and peace among the nations, so that all may share in the banquet of life which God wills to set for the whole human family.
Pope Benedict XVI
I offer cordial good wishes, together with the assurance of my prayers that Almighty God will grant you unfailing wisdom and strength in the exercise of your high responsibilities.
We prefer to wait and see what the practical policies of the American government will be.
Foreign Minister Manouchehr Mottaki
Obama has mobilised the greatest amount of good will and support in all walks of life. This mobilisation of good will is becoming his strength in its own right. And I think all of us expect to translate this occasion into a real opportunity to pacify, to meet, to have a dialogue and bring a solution of peace to all parties concerned.
Prime Minister Ehud Olmert
Palestinian Prime Minister Salam Fayyad
We wish him well and we look forward to active engagement on the part of his administration, in co-operation with important members of the international community.
He came with a change and he needs to change the foreign policy of the United States towards honouring the freedom rights and democratic rights of nations, he must support the freedom of our Palestinian people and their rights and conventions.
Hamas spokesman Fawzi Barhoum
Hopefully the arrival of a new president will mark a real change in relations between the United States and the countries of the Third World, one of respect for sovereignty and the freedom of the people. But nobody here should be under any illusions. This is the North American Empire we are talking about.
President Hugo Chavez
Japan and the United States are allies who share universal values and strategic interests. I am convinced that Japan and the United States, both in a position to lead the world, can build a better future by working together to share knowledge, willingness, passion and strategy.
Prime Minister Taro Aso
With this belief, I wish to join hands with President Obama in further strengthening the Japan-US alliance and striving for peace and prosperity in the Asia-Pacific region and the world.
On the occasion of your assumption of the Office of the President of the United States of America, I am pleased to extend to your Excellency my sincere congratulations and best wishes for your success and happiness as well as for the greater progress and prosperity of the United States of America and her people.
King Bhumibol Adulyadej
I look forward very much to working with President Obama, the next president of the United States. Because we have a huge challenge ahead and it begins by working together on the global financial crisis.
Prime Minister Kevin Rudd
President of the European Commission, Jose Manuel Barroso
We are living through challenging times. And the challenges we face have no respect for national frontiers. What we need is new global governance and a new basis for prosperity. I sincerely believe that Europe and the United States must work together and with our partners around the world to devise and implement this new agenda for globalisation.