(CNN) -- A lockdown imposed Tuesday afternoon at Indiana University-Purdue University Indianapolis has been lifted, according to the school's Twitter account.
Students and staff at the university had been asked to take shelter earlier Tuesday afternoon while police investigated a report of an armed person on campus.
That all-clear message came at 4:36 p.m. "Now returning campus to normal operations," the tweet read. The school did not say whether any gunman had been found.
About 30,000 students go to the school in Indianapolis.
CNN's Jim Kavanagh contributed to this report.