JAFFNA (REUTERS) - Protesters in Sri Lanka criticised the United Nations for a second day on Tuesday during a visit by UN Human Rights Commissioner Navi Pillay who is assessing rights in a country still divided by a 27-year war.

Angry members of the majority Sinhalese community protested in the capital Colombo on Monday, calling on Mr Pillay to get out of the country and stop criticising its rights record.

He visited the northern town of Jaffna on Tuesday, which was at the heart of a bid by members ethnic minority Tamil guerrillas to break away and where protesters criticised the United Nations for not protecting them.

"The UN failed in its responsibility," said Ananthi Sasitharan, a 42-year-old mother of three girls, who holds out hope that her missing husband is alive, perhaps in a secret detention camp.

Her husband, Mr Velayutham Sasitharan, was a top Tamil rebel leader.

Mrs Sasitharan was demonstrating with about 300 other people outside the town's main library where Mr Pillay had a meeting.

They said they had protested after failing in their bid to meet Mr Pillay to discuss their grievances over disappearances and what they see as land grabs by the military.

The Sri Lanka government battled separatist Tamil guerrillas from 1983 until finally defeating them in 2009.

Tens of thousands of civilians were killed in the final months of the war, a UN panel said earlier, as government troops advanced on the rebels' last stronghold.

Many hundreds of people, most of them Tamils like Mrs Sasitharan's husband, simply disappeared.

Mrs Sasitharan said her husband had surrendered to the military on May 18, 2009, a day before the government declared victory over the Liberation Tigers of Tamil Eelam rebel group.

"I am confident that he is alive. He is somewhere in a secret detention centre," she told Reuters.

Mr Pillay's seven-day visit comes after a second United States-sponsored UN resolution in March this year urged Sri Lanka to carry out credible investigations into killings and disappearances during the war, especially in the brutal final stages.

A UN panel said earlier that it had "credible allegations" that Sri Lankan troops and rebels both carried out atrocities and war crimes, and singled out the government for most of the responsibility for the deaths.

Sri Lanka has come under international pressure to bring to book those accused of war crimes and boost efforts to reconcile a polarised country. But it has rejected the accusations of rights abuses.

In July, President Mahinda Rajapaksa, under pressure from the United Nations and the West to address the question of rights abuses during the war, ordered an inquiry into mass disappearances.

According to human rights activists in Jaffna, more than 700 people disappeared in the final phase of the war between 2006 and 2009. Some said loved ones had been abducted by unidentified men in white vans.

Mrs Sasitharan and other relatives of the missing can only hope.

Sri Lanka's military spokesman Ruwan Wanigasuriya said he had no information about Mrs Sasitharan's husband.

"There are lists of all the detainees and the released people after the rehabilitation ... There are records of all of them," he said. "Anybody can get them from police."