BOSTON -- The Massachusetts Institute of Technology says a man carrying a long rifle and wearing body armor was spotted in a campus building, and the school is on lockdown.

MIT said in a statement Saturday that several law enforcement agencies have responded, and a photo that appears to have been tweeted from near campus shows a road blocked to traffic.

The school advises students and workers to stay indoors and report suspicious activity to campus police.

More details were not immediately available.

The Associated Press