Censor.NET reports citing Russian Interfax news agency.
"I'm not an explosive ordnance expert. It's not my job to make such assessments. Only military experts can do it," said Zamir Kabulov, Russia's special envoy to Afghanistan, director of the Russian Foreign Ministry's Second Asia Department commenting on the U.S. strike on the Islamic State tunnel complex in Afghanistan.
"We would like to see the evidence," he said.
Asked whether he shares the view of former President of Afghanistan Hamid Karzai that the U.S. is using Afghanistan as a test site, Kabulov said: "that's what it looks like."
"Having boasted that they dropped the largest bomb on Afghanistan, the Americans declare that this was a successful operation. What exactly was their success in? In the fact that the bomb actually exploded?" the diplomat said.
"What exactly their achievements were? How many Islamic State militants were eliminated? We will be able to talk substantively when the evidence is made public," he added.
Earlier, U.S. forces dropped "the mother of all bombs" - the largest non-nuclear weapon ever used in combat by the U.S. military - on an ISIS tunnel complex in Afghanistan on Thursday. The bomb, known officially as a GBU-43B, or massive ordnance air blast weapon, unleashes 11 tons of explosives.