In the latest round of fighting during the weekend and Monday, at least 19 Tamils rebels and one soldier died in various clashes, the Press Trust of India reported, quoting Sri Lankan officials.
The clashes were largely in Koddaikulam and Nedunkandal regions of Mannar district, in Periyamadu in Vavuniya districts and in the Jaffna area.
Separately, the East Tamil News Agency accused the military of killing six civilians, including two children, in a Claymore mine attack Monday in the Mankulam area.
The report said the victims were on their way to a temple when the mine detonated.
In other reports, Tamil Tiger rebels were accused of shooting and killing the vice chairman of a non-Tiger Tamil party and his assistant Monday in eastern Sri Lanka.
Flooding throughout the country in recent days, triggered by heavy rains, was blamed for at least 16 deaths and displacing about 200,000 people, reports said.
The forecast called for more seasonal monsoon rains in the coming days, raising the threat of more flooding on the Indian Ocean island nation.