Tamil MP Nadaraja’s mother grieves over her son’s body in Colombo on Saturday. (AP)

Colombo, Nov. 11 (Reuters) - A suspected front for Tamil Tiger rebels vowed today to kill majority Sinhalese civilians in southern Sri Lanka in retaliation for the army bombing of a refugee camp this week that killed dozens of minority Tamils.

The High Security Zone Residents’ Liberation Force, which has claimed responsibility for a rash of deadly attacks on troops, made its threat a day after a pro-rebel Tamil MP was slain in the capital.

“Ultimately it would be the Sinhala people who will pay the price for the actions of their sons and daughters occupying the Tamil motherland,” the group, which claims to represent Tamils displaced by army high security zones in the northern army-held Jaffna peninsula, said in a statement faxed to Reuters.

“On several occasions we had warned of every action having an equal and opposite reaction. We regret the retaliatory measures that have been forced upon us, and extend our early condolences to the victims.” The group has also previously threatened to hit hospitals and infrastructure in the south.

Tamil Tiger rebels say 47 people were killed in Wednesday’s attack on the camp, set up in a school in rebel-held territory in the eastern district of Batticaloa. Nordic truce monitors counted 23 corpses, but do not rule out a higher figure.

The international community has voiced outrage at the shelling, and called on the government and the rebels to respect human rights and safeguard thousands of civilians caught in the middle of the two-decade conflict.

Survivors say the rebels provoked the attack by firing heavy guns from near the camp, and the foes accuse each other of using civilians as human shields.