The head of the World Health Organization(WHO) has urged member countries to join a campaign to vaccinate at least ten percent of their population by September. 

WHO Director-General Tedros Adhanom Ghebreyesus made the call on Monday in a speech at the opening of the UN health agency's main annual assembly.

The WHO chief called for a massive push to vaccinate at least ten percent of the population of every country by September.

He criticized the "scandalous inequity" in vaccine distribution, saying that more than 75 percent of all vaccines had been administered in just ten countries. 

Tedros added that a small group of countries that make and buy the majority of global vaccines control the fate of the rest of the world.

He then urged countries to donate vaccines to the COVAX Facility to enable ten percent of the population of all countries to be inoculated by September and 30 percent by the end of the year.