A military official said the fighting broke out Sunday on four fronts, in Jaffna, Vavuniya, Mannar and Welioya regions. He spoke on condition of anonymity, citing government rules.
Rebel spokesman Rasiah Ilanthirayan could not immediately be reached for comment and it was not possible to confirm the report independently because reporters are not allowed into the war zone.
Both the military and the rebels are known to release exaggerated casualty details for their enemy while playing down their own losses.
Tamil Tigers have fought since 1983 to create an independent homeland for ethnic minority Tamils in the island’s north and east. They say they that Tamils have faced decades of discrimination by successive governments controlled by majority ethnic Sinhalese.
Government troops have largely cleared the rebels’ eastern strongholds and have vowed to crush them by the end of this year.
More than 70,000 people have been killed in the violence.