Updated

Zimbabwean police and troops put on a show of force in the capital amid calls for protests against the longtime authoritarian ruler Tuesday.

The calls appeared to have gone unheeded, with no demonstrators on the streets Tuesday.

Armored cars, trucks of riot police and Israeli-built water cannon vehicles had swept through Harare over the weekend, fanning out into townships around the city. Authorities gave no explanation for the display of force. Police were not out in the large numbers seen over the weekend and Monday.

Messages, many of them anonymous, posted on Zimbabwean websites called for protests Tuesday but there has been no open campaigning for demonstrators to turn out on the streets. Some 15 percent of Zimbabweans have access to the Internet and social networking sites.

President Robert Mugabe is scheduled to address a mass rally in central Harare on Wednesday.