CHICAGO (Reuters) - The Transportation Security Administration temporarily suspended passenger screening in one part of Chicago O'Hare International Airport Thursday afternoon to allow agents to conduct a "suspicious activity" investigation, but nothing dangerous was found.

The TSA closed its security checkpoint at Terminal 2 but did not evacuate the facility, which remained open to inbound and outbound flights during the investigation, said Gregg Cunningham, spokesman for the Chicago Department of Aviation.

Nothing dangerous was found and terminal operations returned to normal as of about 4 p.m. local time, according to another Chicago Department of Aviation spokeswoman, Karen Pride.

O'Hare is one of the world's busiest airports.

(Reporting by James Kelleher and Mary Wisniewski)