Russia's Foreign Ministry says a humanitarian convoy which is heading to eastern Ukraine from Russia would cross the border only "under the aegis of the International Committee of the Red Cross."
Russian officials said on August 12 that a convoy of 280 vehicles carrying some 2,000 tons of aid -- from baby food to sleeping bags -- headed from Moscow to Ukraine.
Ukraine's military said it will not allow the convoy into the country unless it is certified by the ICRC.
The Ukrainian military also said the aid would have to be unloaded from the Russian trucks and transferred by the Red Cross to other vehicles.
The ICRC earlier on August 12 said it had no information on what the Russian trucks were carrying or where they were going.
ICRC spokesman Ewan Watson told RFE/RL, "At the moment it is not an International Red Cross convoy, inasmuch as we haven't had sight of the material, we haven't had certain information regarding the content, and the volume of aid that it contains."
The Russian Foreign Ministry said on August 12 the convoy will cross into Ukraine at a border checkpoint in Kharkiv region, away from the areas of the fighting.
The ministry said it was "bewildered" by Ukraine's claims the route had not been agreed with Kyiv, and by "all these new logistic requirements."
Ukrainian and Western officials have voiced concerns that Russia could use the pretext of humanitarian aid to send troops into eastern Ukraine where government forces are fighting pro-Russian separatists.
Ukraine and the West accuse Russia of aiding the separatists with weapons and expertise, and NATO Secretary-General Anders Fogh Rasmussen said on August 11 that he saw a “high probability” that Russia could try to intervene militarily in Ukraine "under the guise of a humanitarian operation."
Western officials have warned against any unilateral military action in Ukraine under any pretext.
With reporting by Reuters and Interfax