Seven years ago, the Chinese smartphone maker Huawei opened a small research centre in Finland, tapping the home country of its rival Nokia for engineers who knew how to build a mobile phone operating system.

Q&A: Google's Huawei ban - what it means for your Android phone

Starting with just 20 engineers, Huawei has gradually built up headcount in Finland, opening bases in Helsinki, Oulu and Tampere in preparation for the day when it might need an alternative to Android, the system that runs three quarters of the world's mobile phones.

On Monday, it appeared as if