Watch out, Android. Apple is nipping at your heals.

New research shows Google Android's mobile operating system, though still immensely popular in the United States, is losing market shares to Apple's iOS.

iPhone's piece of the American market pie grew from 23 percent one year ago to 33 percent while Android's slumped from 61 percent to 56 percent during the same time period.

This is the second consecutive quarter Android's market shares fell.

Android's handset shipments also lagged, down to 13.4 million from 15.3 million during this time last year.

American iPhone shipments rose by 2 million devices during the same period, burgeoning from 5.9 million to 7.9 million.

Still the big kid on the block

Despite its loses, Android maintains a stronghold on more than half the U.S. smartphone market.

The company's market share drop comes at a time when overall smartphone shipments have fallen by 5 percent in the U.S.

While Android's losses may be a reflection of a general trend of decline, iOS shares soared by 10 percent this quarter.

In other smartphone news, more dismal numbers keep popping up for Research in Motion's BlackBerry OS.

The company shows significant market lose for the smartphone as its U.S. shares fell to 6.5 percent from 10.5 percent during that same period one year ago.

Via All Things D