The World Health Organization has called for a moratorium on COVID-19 vaccine booster shots, until at least the end of September, to help ease the drastic inequity in dose distribution between rich and poor nations.

WHO Director-General Tedros Adhanom Ghebreyesus said in a press conference that the move would help towards the goal of enabling "at least 10 percent of the population of every country to be vaccinated."

In July, Israel began rolling out booster shots for people over the age of 60.

Germany said Tuesday it would start offering third doses of the two-shot Pfizer-BioNTech and Moderna vaccines from next month.

Dr. Tedros said he understands why countries want to protect their citizens from the more transmissible Delta variant of the virus but stressed the world's most vulnerable people remain unprotected.

"We cannot accept countries that have already used most of the global supply of vaccines using even more of it," he said.

The United States immediately rejected the appeal.

Speaking to reporters, White House Press Secretary Jen Psaki said, "We definitely feel that it's a false choice and we can do both."

Psaki added that the U.S. has donated more doses than any other country.

U.S. regulators have yet to recommend a third shot for Americans.