In an atypically cryptic press release, General Motors today announced that it will be building a new small car at an unnamed idled UAW-staffed assembly plant here in the U.S. The new vehicle will be in addition to the already-planned 2011 Chevrolet Volt and Cruze, but it's not yet known which small car it will be.

When the new small car will go into production also hasn't been disclosed, though with the Volt set to enter production late in 2010 and the Cruze aiming for an early 2010 release, it could be timed to fit between them, sometime in summer 2010.

One small car candidate is the Chevrolet Spark, born from the long-lived Beat concept revealed in 2007. Other models could also see U.S. production, however, especially with the ongoing brand shuffle at GM, as well as the expected bankruptcy filing coming June 1. It wouldn't be beyond the pale to see a re-branded Opel or Saturn model sold as a Chevrolet, such as the Astra.

"Small cars represent one of the fastest growing segments in both the U.S. and around the world," said Fritz Henderson, General Motors President and CEO. "We believe this car will be a winner with our current and future customers in the U.S.

"This vehicle segment, while important today and expected to be more so in the future, is extremely challenging. It takes a special effort by everyone to bring a domestically produced small car to market in a cost-competitive and profitable way - but that is what we are going to do together [with the UAW]."

The new small car is apparently expected to be a major volume seller, with GM upping its estimate of the percentage of U.S.-built GM sales from the current 67% to over 70% by 2013.