Botswana, the only African country outside South Africa to have reported Omicron cases, said Sunday it had detected 19 infections of the new Covid variant, including the first four declared last week.

"As of today we have recorded a total of 19 cases of the variant," Health Minister Edwin Dikoloti said at a press conference in the capital Gaborone.

The southern African country had on Friday declared that the highly-mutated variant was detected on four foreign nationals who entered Botswana on November 7 on a diplomatic mission.

The announcement was made one day after South African scientists identified the variant, triggering a rush of travel bans on flights from the region.

Most of Botswana's 19 cases came from abroad, Dikoloti said, and many had attended the same event.

Botswana has refused to disclose the provenance of the four diplomats, saying this would further "geo-politicise" the virus.

"We are concerned that there seem to have been attempts to stigmatise the country where it was detected," Dikoloti said, referring to some media reports that described Omicron as the "Botswana variant".

"Detection in this case was treated as origination," he said.

The country of 2.4 million has reported around 194,900 coronavirus cases and 2,416 deaths since the pandemic began.

Just over 20 percent of its population have been fully vaccinated.