CAIRO (Reuters) - Egypt’s public prosecutor on Monday ordered the release of a former diplomat and other opposition figures who have criticized President Abdel Fattah al-Sisi, a judicial source said.

Masoum Marzouk, a former ambassador, and six other prominent opposition activists were arrested in August and have been in prison since.

The activists were held on charges of supporting a terrorist group in achieving its goals and receiving funds for terrorism.

Their release was ordered pending further investigation. The seven opposition figures also include academic Yahya Kazaz and activist Raed Salama.

Marzouk had called for a referendum on Sisi’s rule, in a rare public criticism of the former general.

A second judicial source said the prosecution may decide to shelve the case against them or refer the activists to a criminal court.

Rights activists say Sisi has overseen a relentless crackdown on dissent in Egypt since 2014. At least 60,000 people have been jailed on political grounds, according to a Human Rights Watch estimate.

Sisi has denied holding political prisoners and his backers say the measures were necessary to stabilize Egypt after its 2011 uprising.