Self-driving car software startup Aurora has received investments from its existing partner Hyundai Motor Group, which includes Hyundai Motor Company and Kia Motors Corporation.

The Korean car makers have invested in Aurora as part of Aurora's Series B financing round, contributing to a total amount of about $600 million the U.S. startup has raised. The funding will help Aurora accelerate the development of the Aurora Driver platform.

Baillie Gifford & Co., the top outside investor in Tesla Inc., also participated in Aurora's fundraising round.

Other Series B investors include Sequoia Capital Operations, Amazon.com Inc. and T. Rowe Price Group Inc.

Aurora raised $90 million in its Series A round last year, bringing the total financing to more than $700 million.

Aurora has been working with Hyundai and Kia for the last year to develop the Aurora Driver’s integration into Hyundai’s flagship fuel cell vehicle NEXO. The companies will expand research and development of a self-driving platform for a wide range of Hyundai and Kia’s models.

Earlier this week, Aurora announced a collaboration with FCA US. A day later, Volkswagen AG said it had ended a partnership with Aurora in favor of collaborating on self-driving with Ford Motor Co.

Aurora competes with Alphabet’s Waymo and General Motors’ majority-owned Cruise, among others.