MOSCOW Moscow observed an official day of mourning on Tuesday and nervous commuters returned to the metro, while the death toll from twin suicide bombings on the capital's underground railway rose by one to 39 people.
Flags across Moscow flew at half-mast and sombre Muscovites laid flowers and lit candles at the stations hit by the blasts blamed on North Caucasus rebels.
The police presence was stepped up at Moscow metro stations, and security was tightened on the networks in cities from St. Petersburg to Novosibirsk in Siberia, local media reported.
Entertainment programmes on radio and television were dropped as Moscow observed the official day of mourning for the victims of the deadliest attack to strike the city in six years that was carried out by two female bombers.
Morning commuters warily entered the busy metro system a day after the rush-hour blasts on packed trains at two central stations -- Lubyanka and Park Kultury.
"When I was riding the metro in today, somebody's electronic watch started beeping and I thought, "That's it," said Katya Vankova, a business student. "It was very scary."
Makeshift memorials were set up at both stations.
At Park Kultury, people left red carnations and tied white ribbons to a stand on the platform close to where the bomb went off. Some commuters crossed themselves as they passed by.
The attacks sent a stark message to President Dmitry Medvedev and Prime Minister Vladimir Putin.
Some papers said the attack represented a failure of the government's security policy. They wrote that years of official propaganda had lulled Russians into thinking there was little to fear from the Islamist insurgency in the turbulent and mainly Muslim North Caucasus.
A young injured woman died early on Tuesday, bringing the death toll to 39, Andrei Seltsovsky, the chief of Moscow's health department, said on state-run Rossiya 24 television.
He said that 71 other people were still in hospital, five of them in critical condition, and eight of the victims had been identified. Officials said the bombs that caused the carnage were packed with bolts and iron rods.
At Moscow's central Pushkinskaya station, where three lines intersect, tight-lipped commuters rushed to work past police who patrolled in pairs.
"It was frightening, of course, to go by metro, but I don't really have any other way to travel. I live far away so there was no other alternative," said Oxana Orshan, a student.
Mourning was official only in Moscow, but services for the dead were held at Russian Orthodox churches and other places of worship nationwide.
The bombings -- one at Lubyanka station that serves the nearby headquarters of the Federal Security Service which is responsible for protecting Russia's citizens -- underscored the country's vulnerability to militants.
They sparked fears of a broader campaign of attacks on Russia's heartland by insurgents based in the heavily Muslim provinces along Russia's southern border.
In recent years, rebel attacks have been largely limited to the North Caucasus, although a bombing blamed on the insurgents killed 26 people on a Moscow-St. Petersburg train in November.
Putin, who cemented his power in 1999 by launching a war to crush separatism in the North Caucasus province of Chechnya, broke off a trip to Siberia on Monday, declaring "terrorists will be destroyed."
No group has claimed responsibility for the bombings, but Federal Security Service chief Alexander Bortnikov said those responsible had links to the North Caucasus, where militant leaders have threatened to attack cities and energy pipelines elsewhere in Russia.
(Additional reporting by Dmitry Solovyov)
(Writing by Dmitry Solovyov and Conor Sweeney; Editing by Peter Millership)