Qatar has signed an agreement with drugmaker Moderna Inc to buy its potential COVID-19 vaccine as soon as it is approved and released for global use, state news agency QNA quoted a health official as saying on Sunday.

There are no internationally approved vaccines yet, but several are in advanced trials, including from Pfizer Inc , Johnson & Johnson and Moderna.

"Negotiating early and securing a number of agreements enhances our chances of getting sufficient quantities of the vaccine early," said Abdullatif al-Khal, chair of a national COVID-19 health group and head of infectious diseases at Hamad Medical Corporation.

He did not say how many doses Doha was requesting. Earlier this month, al-Khal said Qatar signed an agreement with Pfizer and BioNTech to supply Qatar with their vaccines.

Moderna (MRNA) said last month it was on track to produce 20 million doses of its vaccine by the end of the year, while maintaining its goal of readying 500 million to 1 billion doses in 2021.

The American group is also working with Swiss group Lonza AG to scale up the manufacturing and production of its potential COVID-19 vaccine to supply markets outside the United States.