Zambian President Edgar Lungu participates in a discussion at the World Economic Forum on Africa 2017 meeting in Durban, South Africa May 4, 2017. REUTERS/Rogan Ward

LUSAKA (Reuters) - Zambian President Edgar Lungu may revoke emergency powers before they expire in 90 days if there is an end to the “acts of sabotage” they were meant to quell, his spokesman said on Wednesday.

Africa’s second-largest copper producer, one of the continent’s more stable democracies, has been unusually tense since the arrest in April of opposition leader Hakainde Hichilema on treason charges, ostensibly for impeding Lungu’s motorcade.

On Tuesday, parliament extended Lungu’s emergency powers by three months in an attempt to quash a spate of arson attacks on market places and court-houses.

Lungu spokesman Amos Chanda said police were making progress in their investigations and had observed no new incidents since emergency rule was imposed a week ago.

“If these acts of sabotage do not continue this should be lifted within three months. It could be revoked even earlier than three months. The president at any point can revoke it,” Chanda said.

Critics say the emergency powers will be used to harass political opponents after last year’s bitter and violent election, which Hichilema’s United Party for National Development (UPND) says was rigged.