The US Central Intelligence Agency has denied the report that a number of its agents have lost their lives during clashes between the Ukrainian army troops and pro-Russia forces in southeastern Ukraine, Press TV reported.
The self-declared mayor of the Ukrainian city of Slavyansk said that in the past ten days the cities self defense units have managed to kill, injure and arrest 650 servicemen among them 70 foreigners.
Vyacheslav Ponomaryov added that 13 CIA operatives have been killed and 12 others sustained injuries.
He also added that 14 officers from the US private security company Greystone and 50 from the Academi security contractor -formerly known as Blackwater- have either been killed or wounded in the clashes.
A CIA spokesperson, however, on the official Twitter page of the US embassy in Berlin rejected Ponomaryov's remarks, saying they do not correspond to reality.
According to recent media reports, private American troops have been fighting alongside Ukrainian military forces in southeast of the country.
Germany's Bild am Sonntag newspaper, citing country's federal intelligence agency BND, reported on May 11 that 400 heavily-armed troops working for Academi security company, formerly known as Blackwater, have been deployed to Ukraine.
The report said that BND informed the German government on April 29 that the American company is aiding the new Western-backed government in Kiev in its military operation against pro-Russian protesters in the country.
Ukraine has been gripped by unrest since pro-Western protesters toppled country's former pro-Russian president back in February.