MOSCOW, Dec. 30 -- Russian experts on Monday urged an upgrade of the terror prevention system after two suicide bombings hit the southern city of Volgograd within 24 hours.

Russia tightened security nationwide after the attacks, which left at least 32 people dead and more than 70 others injured.

"Stopping a terrorist on the spot is not enough. A terrorist must be eliminated before leaving to carry out an attack," said Josef Linder, president of the International Counter-terror Training Association.

He believed that Volgograd was chosen by terrorists because the city is an important transportation hub and a symbol of Russian victory in World War II.

"Countering terror is a continuous work. It includes infiltration of the agents into the terrorists' infrastructure," he told Xinhua.

Linder said the terrorists might be trying to create an atmosphere of panic and to trigger anti-government sentiments.

"Monday's blast is literally a spit into the eyes of the authorities who just declared one day ago the 'yellow level' of emergency in the region," he said.

Meanwhile, federal authorities were certain that the twin bombings could have little impact on the upcoming Sochi Winter Olympics, over which some Western media were casting doubts.

"All necessary security measures have been taken. No additional security measures will be taken in Sochi. Everything necessary has been done," Russian Olympic Committee President Alexander Zhukov told reporters on Monday.

Igor Korotchenko, chief editor of the National Defense magazine, echoed Zhukov, saying: "Despite the attacks, the Sochi Olympics will be successful and security there will be guaranteed on the highest level, because Russia has been in contact with the world's leading special services over the Games' security."

The masterminds of the Volgograd bombings have failed to achieve what they had expected -- alienating people from the government, Korotchenko said.

Instead, people are uniting against extremists, he said.