Villagers in eastern Sri Lanka have found the bodies of three civilians, who were apparently shot and then dumped, police officials say.
Two of the dead men were fishermen
They say that the bodies of two fishermen and an unidentified man were found near the town of Trincomalee.
The UN has given a cautious welcome to a government move to investigate rights abuses by the army and the rebels.
But it says the inquiry could be hampered by "several shortcomings" in Sri Lanka's legal system.
Police say the two fishermen disappeared on Monday. They say that they have no ideas as to the motive for the killings.
Their deaths follow increased violence in Sri Lanka, with reports of more clashes between the government forces and the Tamil Tigers earlier on Tuesday in the north and east.
The defence ministry says that five civilians were wounded by rebel mortar fire near Batticaloa.
Parliament on Tuesday overwhelmingly voted to extend emergency laws intended to give the security forces more power to deal with the violence.
The law, which must be renewed every month by parliament, gives the military and police power to arrest terrorist suspects and detain them indefinitely.
Correspondents say that the escalating violence - coupled with the recent failure of peace talks in Switzerland between the government and Tamil Tigers - adds to the fears of many observers that the country is returning to all-out war.
The acting spokeswoman for the Sri Lanka Monitoring Mission, Helen Olafsdottir, said 1,076 civilians have been killed since the start of this year.
A bus attack in June will be one of the abuses to be examined
The United Nations High Commissioner for Human Rights, Louise Arbour, said in a statement that Monday's announcement by the government that it would set up an internationally-supervised investigation into human rights abuses by both sides in the conflict was welcome.
However she warned that: "Any commission of inquiry can only investigate a selection of cases" and she said that "a broader international mechanism is still needed to monitor, and ultimately prevent, human rights violations in the longer term."
Moreover, she warned that there were "several shortcomings in the national legal system that could potentially hamper the effectiveness of the commission of inquiry, particularly the absence of any legal tradition of establishing command responsibility for human rights violations".
Among the high-profile cases to be probed are this year's massacre of 17 aid workers employed by a French charity, the killing of at least 64 people in a bus attack and the murder of former Foreign Minister Lakshman Kadirgamar last year.