A team of UN experts is set to arrive in Dhaka tomorrow to set a framework for the fact-finding mission that is expected to probe the "atrocities" committed during the unrest that toppled former prime minister Sheikh Hasina.

They are expected to discuss detailed terms and conditions for investigating all the human rights violations that took place between July 1 and August 15, a UN official based in Dhaka told this correspondent yesterday.

"This is the primary UN team of experts before the UN fact-finding mission comes and investigates [the atrocities]. We are expecting to sign an agreement of framework for the probe," a UN official based in Dhaka told this correspondent yesterday.

The delegation will stay here for at least a week and meet the civil society groups, victims of human rights violations, students and government officials and any other actors concerned, the official added.

Foreign ministry officials also confirmed the arrival of the three-member UN team.

According to a primary report of the UN Office of the High Commissioner for Human Rights published on August 16, between July 16 and August 11, 650 people were killed in Bangladesh during the student-led protests and after the fall of the Awami League regime on August 5.

Of these, nearly 400 deaths were reported from July 16 to August 4, while around 250 people were reportedly killed following the ouster of the AL-led government on August 5 and 6, says the report.

The reported death toll is likely an underestimation, as information collection has been hindered by restrictions on movement due to the curfew and the internet shutdown, it says.

The report further says that the number of reported killings in revenge attacks since August 5 still remains to be determined. Those killed include protesters, bystanders, journalists covering the events and a number of members of the security forces, the OHCHR said.

Thousands of protesters and bystanders have been injured, with hospitals overwhelmed by the influx of patients. The majority of deaths and injuries have been attributed to the security forces and the student wing affiliated with the Awami League.

Also, there were a series of attacks on the minorities, including looting and vandalising of properties, places of worship and houses.

During a greet and meet event with the foreign diplomats and international aid agencies on August 18, Chief Adviser to the Interim Government Dr Muhammad Yunus also welcomed the UN proposal of deploying a fact-finding mission, saying the government wants an independent and impartial probe.

"All human rights violations that occurred between July 1 and August 15 will come under the purview of the investigation. However, both the UN and Bangladesh government will need to sign an agreement on the scope of investigation," the UN official said.

The agreement on the framework of the investigation will include the UN experts' access to meet the people they want, obtain documents required for the investigation and the government's commitment not to harass witnesses etc.

Based on the agreement, UN's independent fact-finding mission comprising of five respected legal experts will come to Bangladesh after one or two weeks.

"They will talk to the victims, review videos of rights violation, talk to the government officials, witnesses and whoever they need," the UN official said.

The mission will need six to eight weeks for the investigation and then submit a report including recommendations to the government.

The names of the witnesses or those accused of violence will not, however, be mentioned in the public documents of the fact-finding mission. If the government wants the names of the witnesses or those responsible for the violence, it will provide those to the government for prosecution, UN official added.

The report will put forward recommendations for the government in the prosecution process. If the government wants UN support for prosecution, including in capacity and technical expertise, evidence and even observations, it can extend the support.

"This will depend on the desire of the government," the official added.

A foreign ministry official said the UN mission may also recommend measures for reforms to the law enforcers.