The June 30 fact-finding committee announced on Sunday it would extend its work until Thursday, after receiving new information regarding the dispersal of two camps set up in support of ousted Islamist president Mohamed Morsi last year.
The committee was established by former interim president Adly Mansour to investigate violent acts which have taken place since June 2013. Its deadline is 21 November.
The committee had stated that its Sunday meeting would be its final one.
Fouad Abdel-Moneim Riad, the committee's chairman, nevertheless told reporters on Sunday that the extension of the committee's work was due to the importance of the information it received regarding the dispersal of the Rabaa Al-Adawiya and Nahda sit-ins in which hundreds died.
Mansour ordered the committee's formation last December to gather data and evidence on events that occurred during and after the June 30 protests which led to Morsi's ouster following mass protests against his rule.
The committee's initial deadline was due six months after its establishment. The deadline was nevertheless extended for three months to 21 September. One day before the reaching new deadline, President Abdel-Fattah El-Sisi postponed it once again until 21 November.
The fact-finding committee submitted to Sisi the part of its report, which addresses the situation in the Sinai Peninsula, on 2 November.
Sisi ordered that the committee's full report be made public at an "international press conference" once it is ready for release. Riad said on Sunday that the committee will invite international bodies concerned with human rights to the press conference, including the European Union.
No date has been scheduled for the press conference.
Muslim Brotherhood members have often refused to cooperate with the committee, under the pretext that it is affiliated with the authorities.
Riad has repeatedly described the committee as "neutral" and denied its affiliation with the government.