James Martin/CNET

Google's Android chief, Andy Rubin, hit back against claims it muscled Acer out of using a rival operating system.

In a blog post today, Rubin called out Alibaba's Aliyun platform as a forked version of Android that's modified to the extent that it's incompatible with other Android devices. As a member of the Open Handset Alliance, Acer is forbidden from using such an operating system, he said.

"Compatibility is at the heart of the Android ecosystem and ensures a consistent experience for developers, manufacturers, and consumers," the company said in an e-mailed statement. "Non-compatible version of Android, like Aliyun, weaken the ecosystem."

The response comes after Google was accused by Alibaba of forcing Acerto drop its support of its burgeoning operating system. Acer had originally scheduled a press conference on Thursday to show off the first Aliyun-powered smartphone, but was told by Google that it would cease providing its support if it followed through. As a result, the conference was halted.

Alibaba cried foul.

"Our partner was notified by Google that if the product runs Aliyun OS, Google will terminate its Android-related cooperation and other technology licensing with our partner," Alibaba said a statement e-mailed to CNET on Thursday.

On Friday, Alibaba provided an updated response to Rubin's post.

"Aliyun OS is not part of the Android ecosystem so of course Aliyun OS is not and does not have to be compatible with Android," said John Spelich, vice president of international corporate affairs for Alibaba. "It is ironic that a company that talks freely about openness is espousing a closed ecosystem."

CNET has contacted Acer for comment, and we'll update the story when they respond.

Any company can take Android and create a highly customized, or forked, version of Android. Amazon, for instance, uses its own variation of Android which isn't compatible with other Android devices.

But companies under the Open Handset Alliance, which Amazon and Alibaba aren't a part of, have to run versions of Android that are compatible with its ecosystem, Google said. To have too many versions of Android in the market would be harmful to consumers and developers, it argued.

Under these rules, other OHA members, including Samsung, aren't allowed to use heavily customized versions of Android if they want to further differentiate themselves. That would rule out Samsung using Android to build its own mobile OS, something its leaders have considered.

Google had taken some criticism for seemingly using its clout to squash a burgeoning mobile operating system. Alibaba, an e-commerce company, is known as the Google of China, and wanted to follow Google's playbook and build its own operating system. Google said that while it built its own operating system, Alibaba took elements of Android to build Aliyun.

"We were surprised to read Alibaba Group's chief strategy officer Zeng Ming's quote 'We want to be the Android of China' when in fact the Aliyun OS incorporates the Android runtime and was apparently derived from Android," Rubin said. "Based on our analysis of the apps available at http://apps.aliyun.com, the platform tries to, but does not succeed in being compatible."

Update, 9:21 p.m. PT: Adds a response from Alibaba.