Kiev police said terrorism case into the explosion has been launched. No one was injured by the incident.
"There was no damage to Embassy property. No personnel were injured," the embassy said on its Facebook page. "At this time, we do not consider this incident a terrorist act. The Embassy is working closely with our local partners, and the investigation is ongoing."
It said the "security incident involving a small incendiary device" occurred shortly after 21:00 GMT at the embassy compound.
The Ukrainian Security Service (SBU) also launched an investigation, according to the SBU spokeswoman Elena Gitlyanskaya.
"The security service of Ukraine, the national police and the Kiev prosecutor's office are investigating the circumstances of the explosion, which occurred at the territory of the US Embassy in Ukraine early on June 8, in accordance with the launched criminal proceedings under the article 258 ["terrorist act"] of the criminal code of Ukraine," Gitlyanskaya wrote on Facebook.
Gitlyanskaya added that the details of the investigation would be later provided to the public.
The Ukrainian Foreign Ministry "resolutely" condemned the attack on the territory of the US Embassy in Kiev, adding that additional security measures are being taken to protect the mission, ministry representative Mariana Betsa said Thursday.
"We resolutely condemn the terrorist act on the territory of the US Embassy in Kiev, which could harm the life and health of the diplomatic mission's staff. The law enforcement bodies are taking all measures to investigate the crime. Additional measures are being taken to ensure the security of the diplomatic mission," Betsa said on Twitter.
