Congo is holding its elections under a media blackout and the tense vote is expected to see President Denis Sassou Nguesso prolong his 32-year rule over the oil-rich but poor nation.
Interior Minister Raymond Mboulou wrote to telecommunication companies urging them to shut off telephone, internet and SMS services for 48 hours for “reasons of security and national safety”.
A government source told AFP news agency the shutdown was intended to stop any “illegal” publication of the results of Sunday’s elections.
Tensions have been running high in Congo since October, when a public referendum backed removing a two-term limit that would have kept 72-year-old former paratrooper colonel Sassou Ngeusso from power.
The vote also removed a 70-year age limit for the presidency that could have forced one of Africa’s five longest-serving leaders to step down.
The changes were approved in a referendum by 94.3 percent – dubbed “a constitutional coup” by the opposition – and protests erupted in the run-up to the vote that left several people dead.
The incumbent president has said he has no doubt he will beat his eight rivals, describing election day as a “penalty kick and then victory”.
On Friday, five rival presidential contenders – including former military chief Jean-Marie Mokoko – signed an agreement to back the strongest candidate among them in the event of a second-round vote.