"The risk of China not being able to hold on to second place is very great," Xiao Tian, a Chinese Olympic Committee vice-president told a news conference.
"I am not being falsely modest here, but speaking after analysing numbers," he said, citing boxing, rhythmic gymnastics and a range of athletics events where Russia have title hopes.
After a dismal start, Russia climbed up to fifth in the medals table at the close of Wednesday's action with 14 golds, just behind Australia (16) and Japan (15). China stood second with 24, one behind leaders the United States.
China has surpassed its goal of 20 golds and had led the table in the early days of the Games.
But Xiao calculated that of the 86 gold medals still to be awarded before the Games close on Sunday, China had solid chances at only two more titles --
"Our rivals the United States and Russia are quite prominent in the remaining sports," Xiao said. "We can clearly see that the Russians are catching up."
Chinese sports leaders in Athens and officials back home have consistently sought to dampen gold medal mania, urging their often nationalistic media to curb the hype.
Xiao said Russia could still finish the Games with at least 30 golds even if some titles did not pan out.
Asked if its success at Athens would cause China to raise its target for 2008 when Beijing hosts the Games, Xiao said: "We do not make gold medals the be-all and end-all of the Olympics and to do so goes against the guiding spirit of the Olympic movement."
"China still lags behind America and Russia in overall sports power and this gap cannot be shrunk in a short time."