Egyptian authorities have closed the offices of a prominent human rights group that helps victims of violence and torture, according to the organisation and a police official quoted by the AFP news agency.

El Nadeem Centre for the Rehabilitation of Victims of Violence and Torture in Cairo was shut on Thursday.

"About 15 policemen in official uniform with a group of civilians sealed three apartments in the building belonging to El Nadeem," Aida Seif el-Dawla, a co-founder of the nongovernmental organisation, told AFP news agency by phone.

"We didn't violate any rules and the government has not provided any reasons for its closure decision."

Seif el-Dawla said the centre had filed a lawsuit against the order.

READ MORE: Al Jazeera's Mahmoud Hussein detained for more than 50 days now

A policeman said the centre had been closed for violating the terms of its licence, requesting anonymity because he is not authorised to speak to the media.

Authorities have tried on two separate occasions to shut down El Nadeem Centre amid accusations by human rights groups that the government of President Abdel Fattah el-Sisi is stifling civil society groups.

Rights campaigners accuse the authorities of human rights violations, including forced disappearances, arbitrary arrests and illegal detentions.

Seif el-Dawla was banned from travelling to Tunisia on November 23, along with several other rights activists and lawyers who are not allowed to leave the country.

Strict NGO law

Egyptian and foreign NGOs operating in the country are governed by a strict law which allows the government to supervise their activities and finances.

In November, authorities froze El Nadeem's assets for a week before the organisation submitted a document "proving" the centre is not subject to the law, El Nadeem said.

The organisation was registered with the health ministry and the doctors' union as a "medical clinic", Suzan Fayad, an El Nadeem co-founder, said.

Egypt's parliament approved in November a new law to regulate the activities of NGOs, in a move that prompted fears of an intensified crackdown on such groups.