NAIROBI: Kenya has detected its first three cases of the Omicron variant of Covid-19, the country's health minister said on Wednesday.

"We have at least three cases so far, and have a lot of other samples that we are sequencing," said Mutahi Kagwe.

He said Omicron was detected among travellers -- two Kenyan and one South African -- at airports, but did not specify when and where in Kenya the cases were detected.

Kagwe said those hospitalised with Covid-19 in Kenya were still suffering from the Delta variant of the disease, but cases of Omicron were expected to quickly rise.

"It is just a matter of time before Omicron becomes the dominant variant," he told reporters in Mombasa.

The East African country has seen a surge in Covid infections in recent days after a lull lasting several months.

On Tuesday, the health ministry said the number of tests returning positive results stood at 11.5 percent -- a roughly ten-fold rise on a week earlier.

South Africa to offer vaccine boosters as Omicron spreads

Kagwe ruled out taking "knee-jerk reactions" in response to the Omicron detection, saying any measures taken would be based on science.

"From where we sit, variants will come and variants will go...the decisions we make as a government in order to protect our people must also be measured and calculated," he said.

The WHO warned Tuesday that the variant was spreading at an unprecedented rate and urged countries to act swiftly to rein in transmission and protect their health systems.

Since the new, heavily-mutated variant was first detected in southern Africa last month, it has been reported in 77 countries, according to the WHO.

Early data suggests it can be resistant to vaccines and is more transmissible than the Delta variant, which was first identified in India and accounts for the bulk of the world's coronavirus cases.

Kenya has fully vaccinated only 3.27 million people, or 12 percent of the adult population, according to official figures.

The government hoped to vaccinate 10 million people by Christmas, and 27 million by the end of 2022.

This week, the High Court in Nairobi struck down a government order to prevent unvaccinated Kenyans from accessing services and entering public places such as national parks, bars and restaurants.

In total, the country has recorded 256,815 cases of Covid-19, of which 5,349 have been fatal.