Moscow covertly supplied opposition forces with finances, military equipment and mercenaries. Russia also suspended all civilian flights to Grozny while the aviation and border troops established a military blockade of the republic, and eventually unmarked Russian aircraft began combat operations over Chechnya. The opposition forces, who were joined by Russian troops, launched a poorly organized assault on Grozny in mid-October 1994, followed by a second, larger attack on 26–27 November 1994.[38] Despite Russian support, both attempts were unsuccessful. Chechen separatists succeeded in capturing some 20 Russian Ground Forces regulars and about 50 other Russian citizens who were covertly hired by the Russian FSK state security organization (which was later converted to the FSB) to fight for the Provisional Council forces.[39] On 29 November, President Boris Yeltsin issued an ultimatum to all warring factions in Chechnya, ordering them to disarm and surrender. When the government in Grozny refused, Yeltsin ordered the Russian army to invade the region. Both the Russian government and military command never referred to the conflict as a war but instead a 'disarmament of illegal gangs' or a 'restoration of the constitutional order'.[40]

Beginning on 1 December, Russian forces openly carried out heavy aerial bombardments of Chechnya. On 11 December 1994, five days after Dudayev and Russian Minister of Defense Gen. Pavel Grachev of Russia had agreed to "avoid the further use of force", Russian forces entered the republic in order to "establish constitutional order in Chechnya and to preserve the territorial integrity of Russia." Grachev boasted he could topple Dudayev in a couple of hours with a single airborne regiment, and proclaimed that it will be "a bloodless blitzkrieg, that would not last any longer than 20 December."