The Volkswagen Group has ended ties with self-driving technology firm Aurora, a spokesman for the automaker confirmed to the Financial Times (subscription required) in an interview published Tuesday.

No reason was mentioned though the spokesman confirmed that talks with Ford were “progressing well,” suggesting that a new partnership with Argo AI, the rival self-driving tech firm majority owned by Ford, is imminent.

One of the Financial Times' sources said the deal could be announced by the summer.

VW first announced its partnership with Aurora in early 2018. The goal was to integrate Aurora's self-driving system, known as the Aurora Driver, in VW vehicles and start testing them on public roads by 2021.

Aurora, which was founded in 2016 by the former heads of self-driving car divisions at Alphabet Inc. and Tesla and backed by Amazon, is developing a Level 4 self-driving system capable of fully functioning on its own, though only within set conditions, typically where there is sufficient map data. The startup is working with a handful of automakers including Hyundai and Fiat Chrysler Automobiles.

VW has been developing its own self-driving technology and may turn to Ford to help share the load. The two already plan to jointly develop vehicles and share production capacity, and in March VW's commercial vehicles boss, Thomas Sedran, said forming a mobility joint-venture company was a possibility.