Nato's commander for Libya deflected suggestions today that airstrikes against Muammar Gaddafi's forces were essentially providing cover for advancing rebels.
Canadian Lt Gen. Charles Bouchard insisted the mission was designed purely to protect civilians.
Nato is in the process of taking over command from the US-led, and once complete it could bomb Gaddafi's forces if they are threatening to harm civilian populations.
The UN Security Council authorised countries to take all necessary measures to protect civilians in Libya.
But critics have said the military campaign goes far beyond what was authorised. Russian Foreign Minister Sergey Lavrov said the international air campaign breached the UN resolution and amounted to international interference in what he called Libya's civil war.
Asked where Nato drew the line between protecting the civilians and aiding rebels, Gen. Bouchard said his mission was clear:
"Our goal is to protect and help the civilians and population centres under the threat of attack," he said.
He declined to elaborate on what his rules of engagement were or how he reconciled Nato's stated mission not to take sides in the conflict, saying only that every decision was designed to limit civilian casualties.
But in Brussels a Nato spokeswoman said that the allied operation was launched in response to "the systematic attacks by Colonel Gaddafi against his own people".
"That is how this all started, we have to remember that," she said.
Nato is assuming full command of the operation as ministers from the alliance and countries outside it head to London to co-ordinate strategy on Libya.
France, which took the early lead in Libya by launching the first airstrikes and giving diplomatic recognition to the rebels, has proposed the creation of a political steering committee to oversee operations.
Asked how any decisions from tomorrow's meeting would affect Nato's chain of command, Gen. Bouchard said: "I will be watching it with great interest, and no doubt my commanders will."
The London conference will put in place a steering committee to take over control of the operation from Nato, possibly an arrangement similar to the Peace Implementation Council used for Bosnia during the Balkan wars in the 1990s.
That council was created in 1995 with the aim of mobilising international support for the Dayton Peace Agreement that ended the Bosnian War.
Comprising 55 governments and international agencies, it mainly dealt with economic issues, strengthening Bosnian government institutions and encouraging the return of tens of thousands of refugees and displaced persons.