Google's modular smartphone project has been delayed.

​In a series of tweets Monday, the company confirmed the initial market pilot for Project Ara, which was slated to begin in Puerto Rico later this year, will instead be delayed until 2016.

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Project Ara began in Google's secretive Advanced Technology and Projects (ATAP) group. The aim is to create an Android-based smartphone platform where nearly every piece of hardware, including the battery, processor and camera, is a separate piece of the handset that can be replaced or customized without upgrading to a completely new device.

Google said the latest plan is to bring its modular smartphones to a "few locations" in the mainland United States for the initial rollout, but did not elaborate on the cause of the delay or the change of location.

A spokesperson for Project Ara confirmed the delay to Mashable, but declined to provide additional details around the updated timeline.

The news comes less than a week after the company confirmed it would "re-route" the planned Puerto Rico pilot to a new location, though the company promised the modular smartphones would eventually make its way to the U.S. territory.

Google previously said it chose Puerto Rico as a test ground for the experimental phones due to the island's "incredibly diverse" population, which is divided almost equally between smartphone users and more basic feature phone users.

The company had planned to make handsets available through the territory's two largest carriers, with a variety of devices sold via food truck-like storefronts.

It's not yet clear how or where Google plans to distribute Project Ara devices during the mainland U.S rollout, but the company says more details about the changes will be coming soon