Global leaders hail "historic change" and "victory" in Egypt, but Obama warns of difficult days ahead.
Last Modified: 11 Feb 2011 20:22 GMT
Barack Obama, the US president, said the move was the beginning, not the end, of the transition to democracy in Egypt.
"The people of Egypt have spoken - their voices have been heard and Egypt will never be the same," he said on Friday evening.
He said the people would settle for nothing less than "genuine democracy" and called on the military to ensure a credible political transition.
The US leader added that Egyptians had inspired the world with their moral force and nonviolence, but warned there could be "difficult days ahead".
Earlier, Catherine Ashton, the European Union's foreign policy chief, said Mubarak's decision to quit showed he had "listened the the voices of the Egyptian people" and opened the way to reform in the country.
"It is important now that the dialogue is accelerated leading to a broad-based government which will respect the aspirations of, and deliver stability for, the Egyptian people," she said just after Egypt's vice-president delivered the news on Friday.
"The future of Egypt rightly remains in the hands of the Egyptian people," she said.
"I commend the people of Egypt for the peaceful and courageous and orderly manner in which they have exercised their legitimate rights," Ban said.
"I urge the interim authorities to chart a clear path forward with the participation of all stakeholders."
Angela Merkel, the German chancellor, hailed Mubarak's decision as an "historic change", and called on the country to respect its 1979 peace treaty with Israel.
Her sentiments were echoed by a senior Israeli official, who said: "We hope that the change to democracy in Egypt will happen without violence and that the peace accord will remain."
David Cameron, Britain's prime minister, also urged Egypt to "move towards civilian and democratic rule".
"Egypt now has a really precious moment of opportunity to have a government that can bring the country together," he said.
In China, the official newspaper on Saturday called for stability in Egypt and said foreigners should not intervene.
"Following this extraordinary development, it is hoped that the Egyptian military, government and its people will make every effort to maintain social stability and restore normal order," the China Daily newspaper said in an editorial.
The paper's statement is Beijing's first reaction to the Egyptian leader's resignation.
Meanwhile, Switzerland reacted by saying it was freezing the assets potentially belonging to Mubarak, according to a foreign ministry spokesman.
Echoing other European nations, Greece welcomed the news of Mubarak's resignation.
Greek Prime Minister George Papandreou said Egypt had taken a "great step toward democracy" but warned that the road to reform would be difficult.
"The Egyptians are living a moment of liberation and their country has taken a great step toward democracy," Papandreou said in a statement.
He said the country needed a national consensus on its future and responsible leaders capable of responding to the "expectations of the people," particularly the youth.
"The democratic process in Egypt will be difficult and laborious," he said.
India also welcomed Mubarak's resignation and called for quick elections for a democratic government.
"We were all very concerned about the developments in Egypt and we were hoping that a solution which is Egyptian-led would be found," foreign minister S M Krishna told reporters at the UN headquarters.
"We are very happy that a decision has been arrived at, as a result of which President Mubarak has relinquished office."
'Lesson' for Arab nations
The Arab world was quick to respond to Mubarak's resignation, with Amr Moussa, the secretary-general of the Arab League, saying there was now a "big chance" to build a "national consensus" in the coming period.
The Muslim Brotherhood in Jordan said events in Egypt should serve as a "lesson" for other Arab governments.
"Arab regimes should learn a lesson from what has happened," Jamil Abu Baker, spokesman for the movement, told the AFP news agency.
"Mubarak's departure should have happened from the start. It's only natural after his oppression and corruption [that he has stepped down]. Congratulations to our people in Egypt."
In Gaza, jubilant scenes followed the announcement, with Palestinians setting off fireworks into the evening sky.
"The resignation of Egyptian president ... is the beginning of the victory of the Egyptian revolution," Sami Abu Zuhri, a spokesman of Hamas, which controls Gaza, said.
"Such a victory was the result of the sacrifices and the steadfastness of the Egyptian people," he told the Reuters news agency.
The Emir's royal council in Qatar also said Mubarak's resignation was a "positive, important step towards the Egyptian people's aspirations of achieving democracy and reform and a life of dignity".
Iran said Egyptians had achieved a "great victory".
"The conquest by the will of the great Egyptian nation over the resistance and persistence of officials who were dependent on the world powers is a great victory," Ramin Mehmanparast told Al-Alam television.
However, analysts have remained cautious despite the scenes of jubilation across Egypt.
"Huge questions remain as to where we go next, and it could be a tortuous path," Julien Barnes-Dacey, a Middle East analyst, told the Reuters news agency.
"There must be serious questions over how acceptable Suleiman [vice-president] will be given his support for Mubarak. I think he has to come up with sessions very quickly for very comprehensive reform.
"There will be a feeling of jubilation on the streets in the very short term, but I think if they [authorities] do not seek change protests could still continue."
But in Egypt, opposition figurehead Mohamed ElBaradei said it was the "greatest day" of his life following the announcement. "The country has been liberated," he said.