A women puts a flower outside a wreckage of a trolleybus in Volgograd, Russia, Tuesday, Dec. 31, 2013. Russian authorities ordered police to beef up security at train stations and other facilities across the country after a suicide bomber killed 14 people on a bus Monday in the southern city of Volgograd. It was the second deadly attack in two days on the city that lies just 400 miles (650 kilometers) from the site of the 2014 Winter Olympics. AP Photo/Denis Tyrin Flowers and toys are placed at the site of a trolleybus bombing in Volgograd, Russia, Tuesday, Dec. 31, 2013. Russian soldiers patrol the Battle of Stalingrad memorial in Volgograd, Russia, Tuesday, Dec. 31, 2013. A boy passes candles and flowers laid for victims at an entrance to Volgograd main railway station after a deadly attack by a suicide bomber, in Volgograd, Russia, Monday, Dec. 30, 2013. Russian authorities ordered police to beef up security at train stations and other facilities across the country after a suicide bomber killed 14 people on a bus Monday in the southern city of Volgograd.It was the second deadly attack in two days on the city that lies just 400 miles (650 kilometers) from the site of the 2014 Winter Olympics. A woman cries after laying flowers outside the Volgograd main railway station that was attacked by a suicide bomber Sunday, killing 17 people, including the attacker, in Volgograd, Russia, Tuesday, Dec. 31, 2013. Russian authorities ordered police to beef up security at train stations and other facilities across the country after another suicide bomber killed 14 people on a bus Monday in the southern city of Volgograd. VOLGOGRAD, Russia (AP) - Eerily empty buses lumbered through the streets, police weighed down with body armor warily watched pedestrians near a fast-food restaurant, and members of Cossack units stood guard at bus stops. Volgograd was an ominous and jittery city Tuesday after two suicide bombings in two days killed 34 people. Volgograd authorities canceled mass events for New Year's Eve, one of Russia's most popular holidays, and asked residents not to set off fireworks. All movie theaters were closed until Thursday. People are afraid it will happen again. They're trying not to go outside if they don't have to," said 20-year-old Yulia Kuzmina, a student. We get a feeling that a war has started. That is a worry that extends far beyond Volgograd. Although there has been no claim of responsibility for the bombing of the city's main railway station and a trolley bus, suspicion has fallen on Islamist insurgents, whose leader ordered his adherents over the summer to do all they could to derail the Winter Olympics, which start Feb. 7 in the Russian resort city of Sochi. But even if security at the Games is tight, many analysts suggest that the Volgograd bombings show how public transit in Sochi and sites away from the sports venues are vulnerable. Police reinforcements and Interior Ministry troops have been sent into Volgograd, regional police official Andrei Pilipchuk was quoted as telling the Interfax news agency. He said more than 5,200 security forces are deployed in the city of 1 million, but did not say how much of an increase that was from normal levels. Officers and security guards searched the purses of young women entering a shopping center and waved metal detectors over both males and females. The Cossacks guarding some bus stops added an unsettling note. Although these units are officially authorized volunteer patrols, they are descendants of the fierce horsemen who protected the czars and launched raids on Muslims in the Russian Caucasus, where the Islamist insurgency is now centered. What blasphemy. They did it right before the holiday," said Arkady Chernyavsky, a 73-year-old retiree. He also bristled at how the attacks stained the image of a city that prides itself for the tragic valor of the World War II Battle of Stalingrad, as the city then was called. "This is supposed to be the city of heroes and things like this are taking place," Chernyavsky said. The city's streets emptied out as the last hours of 2013 slipped away. Police cordoned off a 10-meter (30-foot) Christmas tree decorated with lavender lights in the central square, a few hundred meters from the railway station that was bombed on Sunday. Some residents stopped to have their photos taken in front of the tree. Police allowed it but asked them not to loiter. China, host of the 2008 Summer Olympics, expressed confidence Tuesday in the security of the Sochi Games. The competent authorities on our side have maintained close communication and cooperation with Russia in terms of the security work for the Winter Olympics. We believe that Russia is capable of ensuring security and hosting a successful Winter Olympics," Foreign Ministry spokeswoman Hua Chunying said. The U.S. would welcome closer cooperation with Russia on the security preparations, White House spokeswoman Caitlin Hayden said Monday. Associated Press writer Jim Heintz in Moscow and researcher Zhao Liang in Beijing contributed to this report.