The Egyptian authorities arrested then released a journalist who published articles accusing officials of involvement in smuggling cash, weapons and gold to Zambia.
The allegations by Karim Asaad followed the seizure by Zambian officials of a chartered aircraft at Lusaka airport.
It was said to be carrying more than $5m (£3.9m) in cash as well as pistols, ammunition and over 100kg of suspected gold.
Documents – purportedly from a Zambian investigation – had allegedly named several Egyptian army and police officers as suspects.
Egypt’s national press union says Mr Asaad was the 24th journalist to be detained in the country.
Mr Asaad works for the news site Matsda2sh. Colleagues of Mr Asaad have accused security forces of assaulting his wife and child during his arrest on Saturday.