The four countries comprising the Quadrilateral Security Alliance, also known as the quasi-military group called "Quad," are training their guns on China's vaccine diplomacy with a promise to provide over one billion COVID-19 vaccine doses to Asian-Pacific countries by 2022.

The pledge was one of the tangible results of Friday's virtual meeting between the heads of state of Quad's four-member states: Australia, India, Japan, and the United States.

The first ever Quad leaders' summit saw Australian Prime Minister Scott Morrison, Indian Prime Minister Narendra Modi, Japanese Prime Minister Yoshihide Suga, and U.S. President Joe Biden discuss topics of mutual concern in the geopolitical, economic, and military spheres.

Apart from promising to manufacture and distribute more than one billion doses, the four leaders also vowed stronger collaboration toward a rules-based maritime order in Indo-Pacific waters, especially those China illegally claims to own.

A statement issued later said the Quad member states are united in "a shared vision for the free and open Indo-Pacific." The leaders pledged to boost cooperation on "the defining challenges of our time," ranging from the coronavirus pandemic to technology issues.

"We will continue to firmly advance our cooperation to achieve ambitious and concrete results," said Suga.

Quad will address vaccine supply shortages across Southeast Asia and the Pacific by delivering more than one billion doses by the end of 2022 with funding that will allow a huge increase in production capacity in India, the world's leading vaccine maker.

India will use its bolstered manufacturing capacity to make U.S. vaccines such as those from Pfizer Inc and Moderna Inc. Financing for this mammoth effort will come from the U.S. International Development Finance Corporation and the Japan Bank for International Cooperation.

Australia will finance training and provide last-mile logistical support for the distribution of vaccines. Most of the one billion doses will go to the Pacific Islands, Southeast Asia, and Indian Ocean countries.

"The four countries have agreed to a plan to pool their financial resources, manufacturing capabilities and capacities, and logistical strengths so as to ramp up the manufacturing and distribution of the COVID-19 vaccines in the Indo-Pacific region," said Indian foreign secretary Harsh Vardhan Shringla.

"We believe this will speed up the process of post-pandemic recovery and enable families and businesses to put the COVID-19 crisis behind them."

Quad's vaccine diplomacy is seen as a response to China, which has been offering free vaccine doses to developing countries worldwide. China is providing free Chinese-made vaccines to 69 countries and commercially exporting them to 28 more.

In doing so, China is showcasing its global health leadership to lower- and middle-income countries. President Xi Jinpiing has linked the shipment of Chinese-made vaccines and medical supplies overseas to China's "Health Silk Road," which is now a key part of the Belt and Road Initiative.