An 8-story residential building was turned into rubble, killing more than 100 people and destroying the lives of dozens of others.
For the second time in four days, the target was an anonymous house in the working-class suburbs of the capital, which shook Russia to its foundations.
President Boris Yeltsin gave the city mayor Yuri Luzhkov 24 hours for a comprehensive inspection of other residential buildings in the capital.
On Tuesday, Russian officials stated that several tons of explosives were discovered in Moscow, including 3.8 tons in one place.
The Minister of Internal Affairs stated that one building in the south of the city was "virtually prepared for an explosion" when investigators arrived.
Details of an alleged Chechen conspiracy began to appear, aimed at striking fear into the heart of the Russian population and putting pressure on the Kremlin so that it would back away from the conflict in Dagestan.
On Monday, a manhunt was launched for a man using the name Mukhit Laipanov, who recently rented office space on the lower floors of the two residential buildings where the bombs exploded.
Images of a dark-haired man in glasses with a North Caucasian appearance were posted at bus stops throughout Moscow.
The secret services stated that the explosive substances used in the explosions of both residential buildings originate from the Caucasus.
However, the Chechen State Secretary Huseyn Akhmadov insisted that Chechnya "never resorted to such methods of military action to achieve political goals."
A massive operation of the special services came into effect:
Police controlled city metro stations, grabbing anonymous individuals without proper identification documents.
A state of combat alert was introduced at all airports and at nuclear sites.
Mr. Yeltsin addressed the nation on television, stating: "Terrorists are trying to frighten the people of Russia. They are trying to demoralize the state."
Vladimir Putin, the former spymaster turned Prime Minister, also called for calm, saying of the criminals: "It is hard even to call them animals. If they are animals, then they are rabid."
Escalation of Attacks
This was the fourth explosion to strike Russia in less than two weeks.
The bombs were detonated in the early morning hours to maximize damage.
At least 119 people, including 12 children, were killed during the last explosion, the Minister of Emergency Situations stated on Tuesday.
The explosion this week occurred only a few days after an equally powerful explosion that struck another residential building in Moscow at night, killing 93 residents and seriously wounding dozens of others.
A public opinion poll in Russia this week indicated that the deceased Soviet leaders Leonid Brezhnev and Yuri Andropov would have better chances than any of the living politicians to become the next President of Russia if they could appear next year.
Political Fallout
23-29.09.99. Yeltsin in the face of calls for him to resign. Bomb attacks and Caucasian rebels add to the pressure on the besieged President (Amelia Gentleman)
Mr. Yeltsin's reaction to the recent wave of terrorism did not bring him popularity.
While Mr. Luzhkov used most of the PR opportunities provided by the Moscow bombs—comforting victims on the scene under the full attention of television cameras—Mr. Yeltsin remained at his dacha, appearing only once, looking unwell, to tell the nation that Russia's anti-terrorist forces would respond to the attacks quickly and decisively.
Police stated that they found evidence that the explosions were organized by a team led by Chechens and identified the ringleaders as Achemes Gochiyayev, a Chechen, and Denis Saitakov from Uzbekistan.
Mr. Gochiyayev, who used a fake passport in the name of Mukhit Laipanov, rented premises on the lower floors of two Moscow residential buildings that were later blown up. Not a single person was found.