Sri Lanka ? A massive artillery barrage slammed into Sri Lanka’s northern war zone early today, killing hundreds of civilians in one of the bloodiest days of the government’s offensive against the Tamil Tigers, a rebel-linked Web site reported.

The military denied launching the attack, saying it was only using small arms in its effort to wipe out the rebel group.

“There is no shelling taking place,” said military spokesman Brig. Udaya Nanayakkara.

The government vowed two weeks ago to cease firing heavy weapons into the tiny coastal strip that remained under rebel control in an effort to avoid civilian casualties. However, medical officials in the area have reported that air strikes and artillery attacks have continued unabated, despite the presence of an estimated 50,000 ethnic Tamil civilians.

Reports of the fighting are difficult to verify because the government bars journalists and aid workers from the war zone.