A telegram of condolence from head of state Vladimir Putin told Pakistan's leaders of shock at the "barbarous" attack on the school in Peshawar, the Kremlin press service said.
In a message to the president and prime minister on Wednesday, Putin "resolutely condemned the cynical raid by militants and backed Pakistani authorities' efforts to counter the terrorist threat”, wishing speedy recovery to the injured.
The attack on Tuesday killed 141 and injured more than 245, most of them children and teenagers.
Six terrorists were killed in the operation to storm the building and free the hostages.
“On behalf of the Russian government and on my own behalf I express deep condolences in connection with a cruel terrorist attack on a school in Peshawar, inflicting numerous deaths,” the telegram said.
The telegram expressed solidarity with the people of Pakistan, “waging an uncompromising fight against extremists”.
The Russian prime minister asked his counterpart to convey sincere words of support to the next-of-kin of the dead, and wished speedy recovery to the injured.