Authorities have re-opened a Delta Air Lines terminal at LaGuardia Airport after it was partially evacuated earlier Friday when a man left a security checkpoint before finished testing a swab for explosives residue from his shoes, the Transportation Security Administration said.

Authorities are continuing to search for the man, who had put his shoes back on and left the security area before the testing equipment machine sounded an alarm, TSA spokeswoman Ann Davis said.

"We suspect that he did not realize the screening process was not complete, but nonetheless we need to locate him," Davis said.

Outgoing flights at Delta Airlines' terminal D were immediately halted and about an hour later, authorities evacuated the secure area of the terminal beyond the checkpoints while searching for the man.

The TSA says it has placed monitors at the exits to help identify the man.

"We hope to resolve this quickly so as not inconvenience any passengers," Davis said.