BEIJING - Libyan rebels swarmed into the highly symbolic Green Square at the heart of Tripoli early Monday, merely two days after they launched an offensive against the capital in the final push against Colonel Muammar Gadhafi's government.

The obviously minuscule resistance put on by pro-Gadhafi forces marked a sharp contrast with the muscular defiance put up by their embattled leader, who had repeatedly and passionately urged his followers to fight till the end.

Yet the rapid fall of Gadhafi's last stronghold was not beyond imagination, given the rocketing momentum and surging morale the NATO-backed rebel forces had built up since they managed last week to break a months-long stalemate and closed in further on Tripoli.

Meanwhile, with vital supplies of food and oil cut off by the rebels and military power crippled by NATO airstrikes, the Libyan government troops, although better equipped and trained, were unable to stage an effective defense.

Also contributive was the apparent reality that the strength of pro-Gadhafi forces in Tripoli was not as strong as originally anticipated, nor was the loyalty of the local public and military to the man who ruled the country for over four decades.

The suprise advance by the rebels was also a logical outcome of the overall dynamics in and beyond Libya, which had seen the rebels reap more and more gains on both the battleground and the diplomatic front and the government crunch along under increasing pressure.

Although it remains unclear where Gadhafi is now and how he is to react, it is clear that the scale of victory has tipped heavily in the rebels' favor.

As Libya heads for a post-Gadhafi era, however, the troubled North African country faces a host of daunting rehabilitation challenges, given its acute political pains and socioeconomic woes.

The most pressing question is who can fill the power vacuum and lead the severely scathed country in postwar reconstruction and put the life of the over 6.4 million Libyans back on track.

Telling signs have emerged that the primary rebel group, the Benghazi-based National Transitional Council (NTC), is far from monolithic. Internal strife has called its leadership into question, especially since the late July assassination of rebel military commander Abdel-Fattah Younis.

Despite the NTC's pledge to organize a general election and transform Libya into a democratic country, many have voiced the fear that the country of numerous tribes and factions might be reduced to another Somalia.

Without political stability, the recovery of the country's traumatized economy and society would long be in jeopardy, which would in turn leave the Libyan people in protracted misery after six months of violent unrest.

Libya's future is also contingent on the role of foreign powers and international organizations in the reconstruction process. Some countries have apparent reservations in dealing with the Libyan rebels amid fears that terrorists might have infiltrated their ranks.