"As long as Gaddafi is in power, NATO must maintain its operations so that civilians remain protected and the pressure on the regime builds," they wrote in a joint article published in the International Herald Tribune, Le Figaro and Times of London.
"Then a genuine transition from dictatorship to an inclusive constitutional process can really begin, led by a new generation of leaders. In order for that transition to succeed, Gaddafi must go and go for good," wrote US President Barack Obama, British Prime Minister David Cameron and France President Nicolas Sarkozy.
In March, the UN Security Council passed a resolution calling for an immediate ceasefire, establishing a no-fly zone and authorised "all necessary measures" for protecting civilians in Libya. India, China, Russia, Brazil and Germany abstained from voting on the resolution.
Last week, Hardeep Singh Puri, India's envoy to the UN, criticised the Libyan rebels who were fighting against Gaddafi. "And let me stick my neck out here and be provocative," Puri said at a conference on terrorism.
"Countries where the protests have been peaceful there is a better prospect of seeking transformation than in other countries where some misguided have to take up arms and are being encouraged by the international community."
The article said the objective of the Security Council resolution was not to remove Gaddafi by force but to protect civilians.
"But it is impossible to imagine a future for Libya with Qaddafi in power," they said, adding, "It is unthinkable that someone who has tried to massacre his own people can play a part in their future government."
"The brave citizens of those towns that have held out against forces that have been mercilessly targeting them would face a fearful vengeance if the world accepted such an arrangement," they added. "It would be an unconscionable betrayal."
The three leaders also welcomed that the International Criminal Court investigations into crimes committed against civilians and the grievous violations of international law.
Noting that Gaddafi planned to carry out "terrorist attacks" against civilian ships and airliners, they said that that Gaddafi in a leadership role would condemn Libya as a pariah and failed state.
"And because he has lost the consent of his people any deal that leaves him in power would lead to further chaos and lawlessness. We know from bitter experience what that would mean. Neither Europe, the region, or the world can afford a new safe haven for extremists."
