The highly contagious Delta variant of COVID-19 is expected to become the dominant strain of the virus over the coming months, the World Health Organization (WHO) said Wednesday.

The Delta variant, which was first detected in India, has now been recorded in 124 territories - 13 more than last week. It already accounts for more than three-quarters of sequenced specimens in many major countries, the WHO said.

"It is expected that it will rapidly out-compete other variants and become the dominant circulating lineage over the coming months," the UN health agency said in its weekly epidemiological update.