Google dropped a hint via Twitter about its plans for Android Pay, following speculation that this week would see its debut.

“Looking forward to Android Pay? Stay tuned. #soon,” said a tweet from the official Android account.

The tweet followed speculation that 26 August was to be the launch day for the payment service in the US. The speculation was based on a leaked document from fast food chain McDonald’s.

And The Verge spotted an Android Pay logo on a point-of-sale terminal in Subway, another fast food chain, further fuelling speculation.

However, the previous thinking had been that Android Pay will appear as part of the forthcoming Marshmallow update to the Android OS, which is expected in October. That theory now seems more plausible.

NFC-based Android Pay was first unveiled in March this year during Mobile World Congress, with Google revealing further details at the end of May.

Google struck agreements with the following financial institutions to include their credit and debit cards to enable purchases at the point-of-sale: Amex, MasterCard, Visa, Discover, Bank of America, Navy Federal Credit Union, PNC, Regions, NSAA and US Bank.