As they emerged from at the height of the morning rush hour, Muskovites found traffic jams, taxi drivers doubling their prices, and a mobile phone system under severe strain.
Explosions triggered by female suicide bombers in trains at two central underground stations killed dozens in the worst attack on the Russian capital since February 2004.
"I'm scared. In Moscow we live like on a powder keg," Yevgeniya Popova told Reuters television near the Lubyanka metro station, where the first blast hit shortly before 8 a.m.(0500GMT).
Many Muscovites simply soldiered on, looking for alternate routes to work. Some pressed cell phones to their ears as they tried to get through to explain they would be late, to do business, or to make sure loved ones were safe.
Next to Popova, a man in his thirties who was visiting Moscow frowned with frustration after half an hour trying in vain to reach his brother.
"I'm not scared, but I feel like we're at war," he said. "My only feeling is to take vengeance. On whom? I don't know yet.
But it cannot remain unpunished."
There was no immediate claim of responsibility, but security officials linked the attacks to the North Caucasus, where the Kremlin is fighting a growing Islamist insurgency a decade after driving separatists from power in Chechnya.
Popova had no theories about who was behind the blasts.
"Maybe the rebels, maybe Chechnya. Someone is fighting someone.
To be honest, I'm lost." Ekho Moskvy radio said two women wearing Muslim-style headscarves were beaten by four or five passengers on a metro train after the bombings.
Russia is plagued by a strong undercurrent of bias against ethnic minorities from the Caucasus and Central Asia.
Russian media said security agencies were blocking mobile phone connections in the center of Moscow after reports that the bombs were detonated with the help of cellphones. But authorities later said the bombers had blown themselves up.
The second blast hit a metro train in the Park Kultury metro station some 40 minutes after the first explosion.
Both stations are on the red line, which runs close to the Kremlin and is one of the busiest in Moscow. Part of the line was closed and other lines were hit by delays, but the entire system was not shut down.
Announcements informed passengers of delays due to "technical reasons,” avoiding anything more specific.
A number of bomb blasts in Moscow in the late 1990s and early 2000s put residents on guard, with travelers warily eyeing each stray shopping bag or briefcase. But some shed those habits as years passed without an attack.
"I've been walking to work through the entire (Moscow) center because I'm not going to ride the metro today," an unidentified woman told state television Rossiya 24.
RIA news agency said taxi drivers inflated their rates wildly, charging around $100 per journey between some train stations - at least double the usual amount.
The leader of the Russian Orthodox Church, Patriarch Kirill, condemned the attack, and also the taxi drivers.
"This money will do you no good," he said in televised remarks. "Return it, spend it on a good cause. A desire to cash in on someone's distress will only bring you grief."
