COLOMBO (AFP) -- Sri Lanka's rebel Tamil Tigers commemorated thousands of fighters killed in battle amid sporadic clashes with government forces in the island's embattled northeast, the rebels said Saturday.

The Liberation Tigers of Tamil Eelam (LTTE) said they had decorated areas under their control with red and yellow flags and that religious services had been conducted in honor of their "martyrs".

The rebels' Heroes' week celebrations end Monday with a policy statement by LTTE chief Velupillai Prabhakaran, who turns 52 on Sunday.

The pro-rebel tamilnet.com website said the military was moving to disrupt commemorative events inside government-held areas of Sri Lanka's northern Jaffna peninsula.

"Sri Lanka army troopers, Thursday and Friday, have destroyed the platforms erected for the celebrations in the three Heroes' cemeteries and also have razed to the ground several memorial stones," tamilnet.com said.

Both the rebels and the Defense Ministry said that sporadic mortar bomb attacks and artillery duels continued in the island's embattled east, but there were no immediate reports of casualties.

Fighting between the rebels and Sri Lankan government forces has escalated in the past year, claiming over 3,400 lives despite a now threadbare ceasefire agreed in 2002.

The bitter ethnic conflict has claimed at least 60,000 lives since it began in 1972.