By Roland Buerk
BBC News, Colombo
The Tamil Tigers have seen a string of reverses this year
Sri Lanka's military say they have captured a training complex of the Tamil Tiger rebel group, complete with 100 underground bunkers.
The government says its forces are now 15km (nine miles) from Kilinochchi, the rebels' administrative hub.
There is concern over tens of thousands of people displaced by the fighting who are converging on the town.
In recent weeks, Sri Lankan troops have broken through the Tamil Tigers' defences in the north of the island.
They have taken control of towns, villages and bases.
On Saturday soldiers captured a rebel training complex in Welioya after Tiger fighters fled the area.
Military spokesman Brig Udaya Nanayakkara said it contained lecture halls as well as the bunkers.
In fighting elsewhere across the north on Saturday, the military says 27 rebels and seven soldiers were killed.
Repeated attempts to contact the Tigers by phone and e-mail have gone unanswered in recent days.
Government officials have said they aim to defeat the rebels before the year is out and end the island's 25-year civil war.
The United Nations estimates up to 75,000 people have fled the fighting since the start of June and many have converged on the town.
Cabinet Minister Keheliya Rambukwella said the forces were holding back in some areas while the government considered how to get the civilians out.
He accused the Tigers of using them as a human shield.
Relatively few civilians have crossed into government-controlled areas and last week Amnesty International alleged the government was putting those who have into what they called "de facto detention centres".