A top U.N. official called on Sri Lanka's government Thursday to investigate accusations of human rights abuses and to urgently conclude a probe into the killing of aid workers here, according to AP. John Holmes, the U.N. undersecretary-general for humanitarian affairs and emergency relief, said his four-day visit to war-wracked regions of the country was «positive» and he received government assurances that aid workers would be given better access to the conflict zones. The island nation off the southeastern coast of India has been locked in a more than two-decade battle between ethnic Tamil separatists and the majority Sinhalese-dominated government, a fight that has killed more than 70,000 people. A 2002 cease-fire meant to pave the way for a peace deal fell apart in renewed fighting over the past 21 months, much of it centered on eastern Sri Lanka, which the government recaptured last month from the rebels after 13 years. In a report released Monday, the New York-based Human Rights Watch accused the government of human rights abuses _ including illegally detaining opponents and waging battles with little regard for civilians _ in its renewed fight against the Tamil Tiger rebels. The human rights group called for a U.N. human rights monitoring mission here. Sri Lanka has rejected such a proposal as an infringement of its sovereignty. While Holmes declined to discuss the possibility of such a mission, he called on the government to investigate the accusations of abuse in a transparent manner. «These are serious organizations, raising serious allegations about serious problems that need to be dealt with seriously,» he told a press conference. «There needs to be a mechanism that allows people to have confidence in the answers that are being given.» Sri Lanka's human rights minister, Mahinda Samarasinghe, who attended the press conference with Holmes, brushed off the suggested U.N. monitoring mission, saying the government preferred that the U.N. help train its own human rights monitors. U.N. High Commissioner for Human Rights Louise Arbour is expected to address the issue in a trip here in October. Holmes arrived in Sri Lanka on Monday and immediately presided over a ceremony marking the one year anniversary of the killing of 17 aid workers during a battle in the east. He said Thursday that he told the government it needed to push ahead with the investigation into the incident and other attacks on aid workers, up to 30 of whom were killed in the last year and a half. «Those need to be taken forward as rapidly as possible and taken to a conclusion as rapidly as possible,» he said. President Mahinda Rajapakse created a commission last year to investigate human rights violations, including the killing of the 17 aid workers. An international panel he created to monitor the probe has called the commission ineffective and plagued by conflicts of interest. During his visit, Holmes traveled to the isolated northern enclave of Jaffna and eastern Sri Lanka. He also met with top Sri Lankan officials, including Rajapakse. Many aid workers have complained that they have been denied access to war-torn areas in the east. Holmes said the government agreed to provide better access, but he was waiting to see if its words would be translated into actions in the coming weeks. He also appealed to the Tamil Tigers to give aid workers better access _ and to provide for their safety _ in the de facto state the rebels have carved out in parts of the north.