Human rights groups have issued a statement condemning a police raid on the Egyptian Centre for Economic and Social Rights (ECESR).
Ten groups described Wednesday's raid in downtown Cairo as taking place amid a media campaign against NGOs and rights organisations.
"This is a clear effort to crack down on any voice objecting to human rights abuses committed by the interior ministry and security forces. There have been a series of detentions and fake trials of people who object to the actions of the ruling regime," the statement said.
"During the raid six human rights defenders were arrested and held incommunicado: Mustafa Eissa, head of ECESR documentaries unit; Mahmoud Belal, a lawyer; and four volunteers: Hossam Mohamed Nasr, El-Sayed Mahmoud El-Sayed, Mohamed Adel, and Sherif Ashour. Five of the six detainees were released on Thursday morning, but Mohamed Adel is still in detention.
"These human rights defenders were working on a documentary about the Iron and Steel Workers Union strike which was intended to be screened at a press conference today," the statement said.
The groups compared the raid to one that took place at the Hisham Mubarak Human Rights Centre on 3 February 2011.
"These attacks on human rights organisations won't stop us defending people's rights and freedoms," the statement vowed.
Expressing a deep concern for ECESR volunteer Mohamed Adel, the statement called on the government to denounce all raids and attacks on human rights groups. It also called for an immediate and independent investigation into the raid, and a guarantee that rights activists would be able to carry out their work without fear.
The signatories of the statement are: Arab Network for Human Rights Information (ANHRI), Egyptian Association for Community Participation Enhancement, Cairo Institute for Human Rights Studies (CIHRS), Nadeem Centre, Hisham Mubarak Centre, Nazra Institute for Feminist Studies, Association for Freedom of Thought and Expression, New Woman Foundation, Misryoon Against Religious Discrimination, and Egyptian Foundation for Advancement of Childhood Conditions.
The ECESR has resumed it activities and hosted a press conference on Thursday for Egyptian Steel and Iron Company workers.
Lawyer Mahmoud Belal, who was detained in the raid and released hours later, recounted what happened.
"Fifty plain-clothes police raided the office last night shortly before I arrived," Belal said.
"I was detained with five others and blindfolded. If we dared to ask why we were being detained and if the police had a warrant, they would beat us," Belal continued.
According to Belal, lawyers do not know where Adel, a ECESR volunteer and a leading member of the April 6 Youth Movement, is being detained.
Adel is already accused of organising an unauthorised protest at Abdeen court in November.
Security sources claim the raid was for the arrest of Adel, not to target the centre itself.
A number of laptops were also confiscated, Belal added.