No one was hurt when an explosion happened on the grounds of the U.S. Embassy in Kyiv overnight.

Kyiv's police were alerted at 00:05 a.m. on June 8 that an explosion had occurred on the premises of the U.S. Embassy, the press service of the Ukraine's National Police said.

"It has been established during an examination that an unknown person threw an unidentified explosive device into the diplomatic mission's premises. No one was hurt as a result of the blast," the Kyiv police department said on its website.

A group made up of detectives from the district department and the central office of Ukraine's National Police is en route to the scene. A criminal investigation has been launched on a count of a terrorist act. Measures are being taken to identify those who could be involved in the incident.