By Alan Johnston South Asia editor, BBC World Service

A major recruitment drive has swelled military ranks and there has been considerable spending to ensure that the soldiers are better equipped

The rebels have lost control of what was regarded as their capital, the town of Kilinochchi, along with large swathes of territory.

And if the government's account is correct, they've now been routed in the only major town in the area, Mullaitivu.

So, after so many years of war, how has the army managed to get the upper hand so decisively?

It's come to this because several important factors have combined against the rebels. Firstly, over the years, the army has slowly become a more potent force.

Political leadership

A major recruitment drive has swelled its ranks.

There's been considerable spending to ensure that the soldiers are better equipped.

	President has been determined to try to crush the Tigers militarily

Arms have been bought from Pakistan and China, and the air force now has more fighter jets from Israel and elsewhere.

On top of this, the army has re-thought its tactics.

It became better able to cope with the kind of warfare waged by the guerrillas, and started to stretch them thin by opening up a number of fronts.

Analysts also say that the army has fought with more determination recently. It's been less easily deterred when it's suffered casualties.

And this is perhaps a reflection of a much harder line taken by Sri Lanka's leaders.

President Mahinda Rajapaksa, who came to power in 2005, has been determined to try to crush the Tigers militarily, and he has assembled a team at the Defence Ministry that has appeared to be utterly committed to carrying out that task.