"The overall data obtained during a DNA analysis...supports the theory that the remains of Prince Alexei and Grand Princess Maria have been found," the report says.
The bones, found on July 29, 2007, have been examined by a total of 22 experts from 12 different laboratories.
Tests are continuing however. Forensic experts will later compare the DNA extracted from the bones with DNA taken from the blood-stained shirt that Nicholas II was wearing during a failed assassination attempt in Japan in 1890.
The announcement comes on the 90th anniversary of the execution of Russia's last tsar and his family.
Nicholas II abdicated in March 1917, and he and his family were detained by the Bolsheviks after that year's October Revolution. The tsar, his wife Alexandra, and their children, Olga, Tatyana, Maria, Alexei, and Anastasia, as well as a number of servants, were later executed by a firing squad in a basement of a house in Yekaterinburg on July 16, 1918.
Their bodies of all the family, except for those of Maria and Alexei, were found in 1991 and buried in the St. Peter and Paul Cathedral in St. Petersburg in 1998, although the DNA tests confirming that they were Romanov remains have since been challenged.
The initial failure to locate the bodies of Maria and Alexei fueled rumors that they had someone survived.
The Russian Orthodox Church canonized the Romanovs on August 14, 2000.
