The incident occurred on Sunday, September 24.
U.S. Presidential National Security Advisor Jake Sullivan said that the United States condemns the attack on the Cuban Embassy in Washington, D.C., which happened last Sunday.
He noted that attacks on any diplomatic facilities are unacceptable.
"We are in contact with embassy officials and law enforcement to ensure an appropriate and timely investigation, as well as to offer our support for future efforts to protect the diplomatic mission," Sullivan added.
Cuban Foreign Minister Bruno Rodriguez Parrilla said two Molotov cocktails were thrown at the Cuban Embassy in Washington, D.C., on Sept. 24. There were no casualties among the embassy staff.
Cuban President Miguel Diaz-Canel called on the U.S. authorities to respond to the incident and take measures to protect the diplomatic mission.
Last week, the Russian embassy in Armenia was attacked. Unknown persons poured red paint on the doors of the diplomatic mission.