The leader of Zambia's Socialist Party, Fred M’membe, is accused of espionage, which he denies
Four opposition politicians in Zambia - including a former justice minister - have been arrested by police over the last 24 hours for various offences, fuelling concerns that democracy is under threat.
Emmanuel Mwamba of the main opposition Patriotic Front (PF) was detained following a Facebook post in which he called for anti-government demonstrations.
A police statement said he was inciting hatred and violence.
Former Justice Minister Given Lubinda - also of the PF - is accused of refusing to surrender a diplomatic passport.
A third PF member, Raphael Nakachinda, has been charged with espionage, along with Socialist Party leader Fred M’membe, after they featured in a documentary broadcast by Zimbabwe's state broadcaster following that country's election in August.
All four deny the charges.
Civil society groups, the Catholic church and Zambia's Law Association have alleged that the democratic space is shrinking in Zambia.
The government denies the allegation.
