Egypt extended on Wednesday the detention of an Al Jazeera journalist by 15 days pending investigation.
Mahmoud Hussein has complained of bad treatment in detention, not being allowed to contact his lawyer, denied visits from family members, and being held in solitary detention, Al Jazeera has learnt.
Hussein, an Egyptian national, was arrested at his Cairo home on December 20 without charge.
Egypt's interior ministry had earlier accused Hussein of "incitement against state institutions and broadcasting false news with the aim of spreading chaos".
Al Jazeera strongly rejects the charges and says Hussein was in Egypt on holiday and not for work. He visits his family several times a year.
"Al Jazeera deems all accusations against Hussein, including those which might be added later to the current allegations, to be a result of practices which violate international norms and conventions, and which, unfortunately, prevail in Egypt as exposed by human rights organizations," the network stated in a statement.
Hussein, who lives in the Qatari capital Doha, has worked with Al Jazeera in Qatar since 2013.
Shortly after he was detained, state security stormed the homes of Hussein's two brothers and arrested them. They have since both been released.
Egyptian authorities have over the past few years arrested several Al Jazeera employees, raising concerns over media freedom in the country.
In May, a Cairo court recommended the death penalty against Ibrahim Helal and Alaa Omar Mohamed Sablan, charging them in absentia with endangering national security.
Al Jazeera's Baher Mohamed, Mohamed Fahmy and Peter Grestealong with seven colleagues outside the countrywere accused of spreading "false news" during their coverage of demonstrations against a military overthrow of then-president Mohamed Morsi in 2013, the year they were taken into custody.
Baher Mohamed and Mohamed Fahmy spent 437 days in jail before being released. Greste spent more than a year in prison.
Aljazeera