A plane carrying U.S. Democratic presidential candidate Barack Obama made an unexpected but safe landing in St. Louis, Missouri on Jul. 7 due to a mechanical problem.

The snag was detected about one hour after the plane took off from Chicago for Charlotte, North Carolina, Fox News reported.

The aircraft, an MD-80 Midwest charter, experienced a problem with the pitch, or control over the nose of the plane, the pilot said.

Obama, an Illinois Democrat, was sitting in the front of the plane reading the paper when the problem occurred.

A mechanic is looking into the problem on the ground. Obama, his staff, the Secret Service entourage and the press were aboard the plane as the problem was being checked out.