Mozambican security forces deployed on the streets of the capital Maputo on Thursday after rumours of planned anti-government demonstrations circulated on social media, witnesses said.
Several posts on social media in recent days said groups were planning to demonstrate on Friday against government corruption, in particular secret borrowing that could cripple the economy in one of the world's poorest countries.
Armoured vehicles packed with police armed with automatic weapons were deployed on major street corners in Maputo although there was no sign of unrest, two witnesses told Reuters.
Police on Wednesday told the public not to do anything to unsettle the "harmonious coexistence" in the war-scarred former Portuguese colony.
"We will not tolerate any conduct that undermines the order security and public tranquillity," a police statement said, referring to rumours of demonstrations.
The International Monetary Fund said on Saturday that Mozambique had admitted to having over $1 billion dollars of undisclosed debt.
On Thursday, Britain followed the IMF and World Bank in suspending aid payments in light of a "serious breach of trust" created by the recently disclosed borrowing, which analysts say could trigger a serious debt default.
Mozambique's currency, the metical, plunged more than 4 percent amid concerns the aid withdrawal could contribute to an already yawning current account deficit and even hinder Maputo's ambitions to develop vast off-shore gas-fields.
The metical had fallen 55 to the dollar by 1031 GMT, close to a lifetime low of 58.34 hit in late November, according to Thomson Reuters data.