Motorola Mobility has confirmed that it is shutting down the only American plant for assembling customized Moto X smartphones, but promises to continue to unique customization option via Moto Maker.

Motorola Mobility, which is currently undergoing a change of ownership from Google to Lenovo, has taken a big step to shut down its sole Moto X factory in Fort Worth, Texas. The smartphone making company confirmed to the Wall Street Journal on Friday that the American plant will be closed by the year's end, which means Lenovo will have one less item on its acquisition list this year.

The decision to shut down the only American smartphone factory, which was started just a year ago, has raised several questions. It is widely reported that the closure of the Texas plant is a result of high costs to continue operations within the States. The facility heavily focused on shipping Moto Maker products to the US consumers in a matter of two to three days. Customers could customize their handset by choosing different colors for the cover, panel, accents and more through Moto Maker website. The move suggests the Moto Maker feature will be gone along with the factory.

Motorola, however, promised that closing down its US factory will not put an end to its customization options for consumers. The company did not reveal how it will manage shipping customized handsets without a manufacturing plant within the country. Time factor will be a challenging task for Motorola to overcome if it decides to customize handsets outside the US and ship them to the customers.

"[Google's shutdown] suggests that the experience of offering customized phones [in the U.S.] was a failure," analyst Avi Greengart of research firm Current Analysis told VentureBeat. "This plant was unique, designed for rapid customization and shipping within two to three days in the U.S.," he said. "No one was doing anything like it."

Though, the Texas plant wasn't entirely a manufacturing plant, it simple assembled the parts that were built and shipping from China. Motorola had plans to expand its Moto Maker to Europe and Mexico this quarter, but it is unclear if it will still go through with its plans following the closure, Engadget said.