UN Secretary-General Ban Ki-moon has welcomed the announcement of Osama bin Laden's death claiming it as a 'watershed' in fight against terrorism.
Governments and leaders praised the killing of Osama bin Laden as a dramatic success in the war against al-Qaeda that would make the world a safer place.
British Prime Minister David Cameron said Bin Laden's death would ‘bring great relief to people across the world’.
‘Osama bin Laden was responsible for the worst terrorist atrocities the world has seen,’ Mr Cameron said in a statement.
‘It is a great success that he has been found and will no longer be able to pursue his campaign of global terror.’
European Parliament President Jerzy Buzek said: ‘We have woken up in a more secure world.’
President Nicolas Sarkozy hailed the killing as a major coup in the fight against terrorism, but both he and Foreign Minister Alain Juppe warned it would not spell the demise of al-Qaeda.
German Chancellor Angela Merkel told President Obama that she was relieved about the killing of Bin Laden.
Italian Prime Minister Silvio Berlusconi has hailed the killing of Osama bin Laden as a 'great outcome in the fight against evil.'
He continued, 'the world has been waiting for this news for 10 years.'
'This is a great outcome in the fight against evil, in the fight against terrorism, a great outcome for the US and for all democracies.'
The US had succeeded in making a decisive strike against al-Qaeda, Ms Merkel's spokesman Steffen Seibert said in a statement.
But the chancellor warned that international terrorism has not yet been defeated.
'With the commando operation against Osama bin Laden and his killing, US forces succeeded in making a decisive strike against al- Qaeda,' Ms Merkel's spokesman said in a statement.
'Chancellor Angela Merkel expressed her relief about this news to US President Barack Obama,' Seibert said.
'Osama bin Laden was responsible for the deaths of thousands of innocent people...The forces of peace were successful last night. International terror has not been defeated. We'll all have to remain vigilant.'
Russia welcomed the killing of the al-Qaeda leader.
‘Revenge is inescapable for all terrorists,’ news agencies quoted the Kremlin press service as saying in a statement.
‘Only a joint struggle against global terrorism can bring a result,’ the statement added. ‘Russia ready to increase its cooperation.’
The news was greeted with celebrations in Israel.
‘This is a resounding triumph for justice, freedom and the values shared by all democratic nations fighting shoulder to shoulder in determination against terrorism,’ Prime Minister Benjamin Netanyahu said.
The Taoiseach has said the removal of Bin Laden's ability to plot heinous acts is a major achievement in the effort to rid
the world of the threat of terrorism.
Enda Kenny said the international community cannot let up in its efforts to address the threat that terrorism continues to pose for us all.
He said Ireland will continue to work within the framework of the UN, the EU and the broader international community to address the 'scourge of terrorism and its root causes.'
Meanwhile, the Minister for Tourism, Transport and Sport has said he does not think the killing of Osama bin Laden will have any implications for the impending visit of the US President to Ireland.
Leo Varadkar said that the necessary security arrangements have been put in place for Barack Obama's visit, which is due to take place later this month.
Markets reacted positively to the news and lifted the US dollar from a three-year low and raised stock index futures.
US crude oil prices also fell, but analysts said any market impact would be short-lived.
In Afghanistan, which US-led forced invaded in 2001 to root out Bin Laden and the militant Taliban who sheltered him, President Hamid Karzai called on the Taliban to refrain from fighting.
‘The Taliban must learn a lesson from this. The Taliban should refrain from fighting,’ Mr Karzai told a news conference.
Most analysts agreed that although the killing of such an inspirational figurehead would deal a blow to his followers' morale, Bin Laden had not had any significant practical role in the organisation for years.
Al-Qaeda works in a decentralised way so the direct impact of Bin Laden's death would be limited.
While their leaders were proclaiming that the world had become safer, many countries were preparing their citizens for the worst.
The US State Department warned Americans worldwide of ‘enhanced potential for anti-American violence’.
‘Given the uncertainty and volatility of the current situation, US citizens in areas where events could cause anti-American violence are strongly urged to limit their travel outside of their homes and hotels and avoid mass gatherings and demonstrations,’ the State Department said in a statement.
Australia issued a similar warning. In countries with significant Muslim populations, international schools, embassies and other potential targets were putting extra security measures in place in case of reprisals.
India, whose ties with Pakistan are strained, was one of the more ambivalent countries to the news. India has long accused its neighbour of allowing terrorist groups to operate unhindered on its soil.
A statement from India's foreign ministry praised the killing of Bin Laden as a ‘victorious milestone’, adding: ‘The struggle must continue unabated.’
But a home ministry statement pointed to the fact that far from hiding in a remote cave, Bin Laden was found in a mansion 60km from Islamabad.
This, it said, raised ‘concern that terrorists belonging to different organisations find sanctuary in Pakistan’.
Pakistan said that Osama bin Laden's death was a major setback to terrorist organisations around the world.
‘This operation was conducted by the US Forces in accordance with declared US policy that Osama bin Laden will be eliminated in a direct action by the US Forces, wherever found in the world,’ the foreign ministry said in a statement
Kenya's prime minister hailed news of the death of Osama bin Laden, but said more must be done to bring stability to neighbouring Somalia, where al-Qaeda-linked fighters are waging an insurgency.
Al-Qaeda carried out simultaneous suicide bomb attacks on US embassies in the Kenyan capital Nairobi and Tanzania's main city Dar es Salaam in 1998, killing hundreds of people.
Yemen welcomed the US operation with one official expressing hope that more measures would further root out militancy.
‘We welcome the operation that was completed, and we hope that targeted measures will be taken to end terrorism throughout the world,’ he said.