A university employee in the US city of Boston was wounded after a package delivered to the institution exploded while he was handling it.
The Northeastern University employee, 45, was taken to hospital to treat the wounds to his hands on Tuesday, Boston police Superintendent Felipe Colon said.
CBS News reported that the case contained a “rambling” note criticising virtual reality and Facebook founder Mark Zuckerberg.
A second package was found and declared safe, police said. They did not reveal how the packages were delivered to the urban campus.
“A search revealed a second similar package that was ultimately rendered safe by our bomb squad. I will tell you that the scene is secure in that the investigation is ongoing,” Mr Colon said.
The police bomb squad, the Boston Fire Department and Boston Emergency Medical Service were among those investigating the incident, police said.
Evening classes that were to be held in six buildings were cancelled, campus police said on Twitter.
Police at other Boston-area campuses, including Harvard University and the Massachusetts Institute of Technology, urged people to be cautious and asked them to report any suspicious packages.
The city was rocked by the Boston Marathon bombings of 2013, when three people were killed and more than 260 others wounded by a pair of home-made bombs at the annual race.
In 2015, a jury convicted Dzhokhar Tsarnaev and sentenced him to death for helping to carry out the attacks along with his older brother Tamerlan, who died several days after the bombings in a gunfight with police.
The gunfight ended when Dzhokhar ran his brother over with a stolen car as he fled the scene.
