Yahoo has hit back at Microsoft after it blamed the web giant for apparently random spikes in data usage experienced by some Windows Phone 7 users.

"Yahoo Mail is widely available on tens of millions of mobile phones, including those running on Apple iOS, Android, Nokia Symbian, and RIM. The issue on the Windows Phones is specific to how Microsoft chose to implement IMAP for Yahoo Mail and does not impact Yahoo Mail on these other mobile devices," the company said.

Over the past few weeks, some Windows Phone 7 users have complained of occasional very high data use on their handsets. The usage seems to take place without any action by the users. The handset also relies on the 3G connection, even when a Wi-Fi connection is available.

Last month, Microsoft confirmed there was a glitch but until yesterday refused to name the "third-party solution commonly accessed from Windows Phones" that was causing the issue.

The glitch is caused by an error in the code that instructs Windows Phone 7 handsets on how to download mail from Yahoo, and means up to 25 times more data than necessary is being downloaded.

Yahoo added that it has "offered to provide Microsoft a near-term solution for the implementation they chose, and is encouraging Microsoft to change to a standard way of integrating with Yahoo Mail, which would result in a permanent fix."

See also: Windows Phone 7 smartphones sales hit 1.5m