Officials said Thursday's attacks took place in the northeastern Trincomalee district, which lies in the Muslim-majority port city of Muttur, during clashes between troops and rebels in the streets.
Two constables and two paramilitary troopers were also killed in the fighting, the officials added.
Meanwhile, the Sri Lankan air force resumed its air strikes on Tamil Tiger positions, Reuters news agency reported. The army said more than 40 rebels were killed on Wednesday.
Fighting between the two sides broke out last week when the Sri Lankan army launched a massive ground offensive to take control of the Maavilaru reservoir which supplies water to more than 50,000 people in an army-held area.
More than 156 people have been killed, and at least 100 others wounded in the fighting so far.
"The government must take responsibility for the killing of civilians," Muslim leader Rauf Hakeem said. "Both sides must stop the attacks immediately and go back to the positions they had before the (2002) truce."
Mr Hakeem also accused the Sri Lankan government of firing the shells that fell on the school sheltering civilians.
"The people were killed in attacks carried out by the security forces," Hakeem said.
The Sri Lankan army denied the accusations, blaming the attacks on the Tamil Tigers.
The 2002 ceasefire halted a two-decade civil war that has killed more than 65,000 people since 1983. But tensions between the Tigers and Colombo have been escalating since last November. Peace talks have been canceled, and violence has claimed the lives of more than 800 people.
Last week's clash over water supplies south of Trincomalee was the first time the two sides had fought in a ground battle since the truce.
Colombo says that it is still committed to the truce, accusing the Tigers of attempted ethnic cleansing through cutting off the water supply to around 50,000 mostly Sinhalese and Muslims.
"Denying civilians water is a war crime," said Dr. Palitha Kohona, head of the government's peace secretariat. "Wars have started over less. Look at Lebanon."
On the other hand, the Tigers say their attacks are aimed at stopping "military attacks against civilians" under the pretext of securing water.
"This certainly looks like a war. Neither side has shown any sign of wanting to de-escalate this situation and seek peace," one diplomat said.
Source:Islamonline.comLast Mod: 20 Eylül 2018, 18:16