The only operational runway at Charleston International Airport, which is jointly used by Charleston Air Force Base, was shut down for more than an hour Saturday afternoon after something fell off an airplane and caused a small grass fire, a Joint Base Charleston official said.

The shutdown caused two flights to be diverted after a ground emergency was declared at 4:07 p.m. An Air Force crew extinguished the small grass fire on the runway’s approach and shut the runway down to conduct a sweep after finding metal debris on it, Air Force spokeswoman Rose Alexander said.

“Our folks came to look at the debris to see if it was from a military aircraft,” Alexander said. “It was not from one of our C-17s.”

A Mesa Air flight for US Airways from Charlotte was diverted to Savannah, and a Shuttle America flight for Delta from Detroit was diverted to Savannah as well, spokesmen for US Airways and Delta confirmed Saturday. Both flights later returned to Charleston.

A Southwest flight to Chicago took off at 4:04 p.m., and the pilot reported striking something on the runway, according to Southwest spokesman Brad Hawkins. The flight landed in Nashville, Tenn., as a precaution to be checked out. Nothing wrong was found, and it continued on to Chicago, he said.

“(The debris) did not come off of our airplane,” Hawkins said.

A Boeing 787 was seen taxiing on the runway before the incident was reported.

Boeing is expected to issue a statement shortly, according to spokeswoman Candy Eslinger.

The runway closed around 4:30 p.m. and reopened at 5:41 p.m., according to airport spokeswoman Becky Beaman.

The airport is down to one runway because the main 9,000-foot runway is undergoing a complete overhaul over the next several months.

Check back here later for more details and in tomorrow’s editions of The Post and Courier.