CAIRO: Egypt has freed a journalist for Qatar's Al Jazeera, a security source said Friday, after four years in jail without trial following the end last month of a rift between the two Arab states.

Mahmoud Hussein, an Egyptian national who had been imprisoned since December 23, 2016, was released on Thursday night, the Egyptian security source told AFP without elaborating.

But Gamal Eid, head of the Arab Network for Human Rights Information, said that while the decision to release Hussein had been taken, "he has still not returned home and is still being held".

The 54-year-old was detained in Cairo when he returned for a family holiday, and was accused of incitement against state institutions and spreading false news.

Qatar's Al Jazeera -- which has run a daily campaign calling for his liberation -- did not immediately confirm his release. It has repeatedly said he was being held "without formal charges nor trial".

Hussein's reported release comes two weeks after Egypt and Qatar restored ties, following a three-year Saudi-led freeze on relations with Doha.

Egypt, along with the United Arab Emirates and Bahrain, followed the lead of Gulf powerhouse Saudi Arabia and cut ties with Qatar in June 2017, alleging it backed radical Islamist groups and was too close to Riyadh's rival Iran -- claims Doha denied.

Ties were restored following a Gulf summit held in Al-Ula, Saudi Arabia last month.

"Releasing Hussein could indicate a sign of goodwill from Cairo to Al Jazeera that it wants a thaw in its relations with the news channel," said King's College London assistant professor Andreas Krieg.