Rebel fighters waved opposition flags to celebrate victory in Tripoli's Green Square on Aug. 21, 2011.

NATO Secretary General Anders Fogh Rasmussen said early Monday in Brussels that Gaddafi's 42-year rule in Libya is "clearly crumbling," while urging the pro-Gaddafi forces to stop resistance and spare the Libyan people "further bloodshed and suffering."

He said "NATO is ready to work with the Libyan people and with the Transitional National Council, which holds a great responsibility."

"They must make sure that the transition is smooth and inclusive, that the country stays united, and that the future is founded on reconciliation and respect for human rights," he added.

US President Barack Obama is expected to make a statement on the Libyan situation soon. White House spokesman Josh Earnest said earlier that Gaddafi's days "are numbered."

British Prime Minister David Cameron said in a statement that "it is clear from the scenes we are witnessing in Tripoli that the end is near for Gaddafi."

French President Nicolas Sarkozy Sunday said that Gaddafi should give up "immediately what power he has left" as a rebel victory is "no longer in doubt."

Venezuelan President Hugo Chavez lashed out Sunday at Western powers for "destroying Tripoli with bombs," saying that "let's pray for the Libyan people."

Libya has been embroiled for months in the deadliest turbulence that swept West Asia and North Africa after its initial eruption in Tunisia.

Some Western powers militarily intervened in March under the name of a UN resolution adopted to protect Libyan civilians, and NATO took over control of the mission weeks later.