MOSCOW, June 16. /TASS/. Biological laboratories in Ukraine overseen by the US were studying viruses capable of being transmitted by mosquitoes, spreading, among others, Dengue fever, Chief of Russian Radiation, Chemical, and Biological Protection Force Igor Kirillov said on Thursday.

"The stated goal of the project was the study of viruses capable of infecting Aedes mosquitoes. In accordance with the technical specification the viral preparation was developed by an institute in Kiev and delivered to the US to conduct air biological field research," he said.

According to the military official, the interest of US clients to the mosquitoes that transmit such infections as Dengue fever, Zika fever and yellow fever is not accidental: during the last major yellow fever outbreak in Africa in 2011, some 170,000 cases of a severe form of the disease were recorded resulting in 60,000 fatalities.