Staff member Georgina Wilson prepares a drone for the delivery of medical supplies at the service base run by operator Zipline in Ghana in 2019. The US firm has raised new funding for expansion.

US-based drone operator Zipline, which has seen pandemic-fueled growth of delivery of vaccines and medical supplies in Africa and the United States, said Wednesday it raised $250 million as it moves to expand globally.

The latest round valued the California-based startup at $2.75 billion and will be used to fund "expansion into new industries and geographies" including "instant" , the company said in a statement.

Zipline, which calls itself "the world's largest automated on-demand delivery ," said it hopes to eventually service residential consumers as it seeks to compete with rival automated services including from Amazon for ultrafast deliveries.

"We have completed hundreds of thousands of deliveries of blood, medicines and vaccines, and today Zipline makes a commercial delivery every four minutes," said Zipline founder and chief executive Keller Rinaudo in the press statement.

"In the past year, we have seen major growth in every market, including the US," he added. "And we're continuing to build on our proven track record and technology to bring instant logistics to more partners, communities and people."

Zipline, founded in 2014, began by delivering by drone in parts of Africa and expanded services during the pandemic to distribute and Covid-19 vaccines in Ghana and in the US state of North Carolina.

During the pandemic, the company experienced record growth, seeing an uptick in demand for contactless service as did similar robotic delivery services.

The growth period saw the company expand to round-the-clock autonomous service in Rwanda, add four additional distribution centers covering 90 percent of Ghana's population and develop new partnerships with medical suppliers Kaduna and Cross River States in Nigeria, Toyota in Japan and Walmart in the US.

The funding round included Fidelity, Intercorp, Emerging Capital Partners and Reinvent Capital, joining existing investors including Baillie Gillford, Tamasek and Katalyst Ventures.