MILAN (Reuters) - Biathlon's governing body (IBU) has dropped proceedings against 22 of the 29 Russians who were placed under investigation last month following the McLaren report due to lack of evidence, it said on Saturday.

The IBU, however, said it had opened a formal investigation into the Russian biathlon union (RBU) which had been given until Feb. 9 to provide a "detailed and fully documented report" on the remaining seven cases.

Russia last month pulled out of hosting a World Cup biathlon meeting in Tyumen in March following the publication of the second part of the McLaren Report into Russian doping which revealed an institutional conspiracy to conceal positive tests.

The junior world championships, earmarked for Ostrov, were also handed back to the IBU which opened the investigations last month when it also suspended two unnamed Russian athletes.

At a meeting in the Italian resort of Anterselva on Saturday, the IBU said its executive board decided to further investigate seven individual athletes.

"There is no sufficient evidence for the other athletes for the time being," it said, adding that the IBU will open formal investigation against the RBU.

"The RBU is to provide the IBU with a detailed and fully documented report with respect to the seven cases under investigation," it said ahead of the next IBU meeting on Feb. 9.

(Writing by Brian Homewood, editing by Ed Osmond)