BRUSSELS -- The European Union (EU) will receive an additional four million doses of BioNTech-Pfizer COVID-19 vaccine by the end of March to address the need in virus hotspots, the European Commission announced on Wednesday.

The executive arm of the EU reached an agreement with the manufacturer for the extra doses to be delivered in the next two weeks to its member states, in a bid to "tackle coronavirus hotspots and facilitate free border movement," said an EU press release.

The release noted that new variants of the coronavirus have caused increased infections in hotspots like Tyrol in Austria, Nice and Moselle in France, Bolzano in Italy and some parts of Bavaria and Saxony in Germany.

"The BioNTech-Pfizer vaccine has proven highly effective against all currently known variants" of the coronavirus, the release added.

The additional jabs will help the EU member countries keep the virus spread under control, and help ensure or restore free movement of goods and people, said European Commission President Ursula von der Leyen.

Germany, Belgium, Hungary, Finland, Denmark and Sweden have shut down national borders to tackle the new variants. The European Commission has urged them to replace the travel ban with more proportionate and targeted measures.

The extra doses will be available to all EU member states "on a pro-rata basis according to their population," said European Commission spokesperson for health Stefan de Keersmaecker.

The commission has ordered 600 million doses of BioNTech-Pfizer vaccine, the biggest early purchase agreement among the six ones that secure 2.6 billion doses in total for the EU.

With three COVID-19 vaccines approved by the European Medicines Agency, the bloc has rolled out a vaccination campaign aiming at inoculating 70 percent of the adult population by Sept 21.

Meanwhile, 263 candidate vaccines are still being developed worldwide -- 81 of them in clinical trials -- in countries including Germany, China, Russia, Britain, and the United States, according to information released by the World Health Organization on Tuesday.