Fourteen people have been arrested in Zimbabwe for circulating an e-mail calling for protests to oust President Robert Mugabe, state media reports.
Mr Mugabe is protected by tough security laws
The government-controlled Herald newspaper says the e-mail urged people to take part in marches on Monday.
It is not clear how the police found the e-mail but the state security services have been trying to acquire high-tech snooping devices.
The 14 have all been released on bail, the paper reports.
The e-mail allegedly called on people to take part in "violent demonstrations and strikes to push Robert Mugabe out of office".
It complained, among other issues, of hyper-inflation, high income tax, unemployment, shortages of goods and services, and "propaganda on the radio, TV and newspapers".
Since the closure of the only non-state-owned daily newspaper in September, it has been difficult for opposition groups to spread their message as the government controls all radio and television stations.
Among those Zimbabweans rich enough to have access to computers, this has left e-mails as one way to carry on political activity.
A senior official from a Zimbabwean internet service provider (ISP) told BBC News Online that he did not believe the security services had obtained the cyber-monitoring equipment they have been seeking.
The government has closed the only non-state daily newspaper
He said the e-mail had probably been forwarded to someone who had sent it to the authorities.
But he also said that it would be easy for an ISP to monitor any e-mails it sent and state-owned companies might be coming under pressure to help the government track down opposition activity in cyberspace.
Some 90 people were arrested on Tuesday for taking part in a union-organised march against the worsening economic situation and alleged state harassment.
A strike called to protest at the arrests failed to take hold on Thursday and Friday and unions said one reason was the "news blackout".
As the economic and political situations have worsened, the government has passed a series of tough laws to clamp down on protests.
President Robert Mugabe's opponents accuse him of economic mismanagement, and blame the country's woes partly on the seizures of white-owned farms.
Mr Mugabe says his land reforms are designed to redress an injustice of British colonial rule, and accuses opponents at home and abroad of sabotaging the economy.