Speaking to RIA Novosti, the spokesman said that Konstantinov and another soldier were killed earlier in fighting with enemy militants.
"On May 3, 2017, during fighting, Captain Konstantinov saw that his comrade-in-arms had been wounded and could not fight off the terrorists. He rushed to help. But the forces were unequal. Evgeny received six bullet wounds. The second soldier was also killed," the spokesman said.
Konstantinov grew up in a military family. He graduated from high school in Birobidzhan, the administrative center of the Jewish Autonomous Region, in 2002, and entered the Novosibirsk Military Institute.
In Syria, he served as a military advisor, helping the Syrian Army with the training and education of Syrian troops.
Konstantinov was 32 years old.
Over 30 Russian soldiers, contractors, and support personnel have died in the Syrian anti-terrorism operation. Launched in September 2015, the Russian military's operation has fought to liquidate thousands of Islamist radical fighters in the Middle Eastern country.
Jihadists flocked to Syria to try to overthrow the country's internationally recognized government starting in 2012. At various periods, the Islamist forces, including al-Qaeda, Daesh (ISIS), and other groups, are believed to have received the backing of several foreign governments, including Saudi Arabia, Qatar, Turkey, and the United States. In addition to setting up a self-proclaimed 'caliphate' in Syria and Iraq, Daesh has launched repeated terror attacks against civilians in Europe, North America, Africa, and Asia. In the last two years, Syrian Army forces backed by Russian air power have made significant gains in liberating the country from Islamist control.