A Soviet-era laboratory houses samples of smallpox and Ebola

A gas explosion rocked Monday in Siberia a laboratory of biological weapons of the Soviet era, which houses samples of Ebola and smallpox.

At least one employee was injured in the blast or fire that followed.

Vector, the national center for research in virology and biotechnology of the city of Koltsovo, near Novosibirsk, announced that a gas tank explosion had caused the fire.

The explosion took place during repairs in an inspection room located on the fifth floor of a six-storey concrete building, according to a Vector release.

"No work with biological material was done in the building," the statement said. "A worker was injured."

A spokesman for Vector told ABC News: "There is no danger to life, there is no biological disaster, we are working in normal mode."

Vector is one of two known sites harboring live samples of the smallpox virus. The other is the Centers for Disease Control and Prevention in Atlanta.

Founded in 1974, Vector is one of the largest research centers in the world. In the Soviet era, researchers at the laboratory studied potential wounds, including coal and tularemia, to learn more about creating biological weapons. Vector is now developing tools for the diagnosis and treatment of infectious diseases, including work on vaccines against swine flu, HIV and Ebola.

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Earlier this year, Vector had completed testing of an Ebola vaccine that would be ready for use.

In 2004, a scientist working for Vector died after being accidentally stuck with a needle marked with Ebola. Scientists and officials said the accident had raised concerns about the safety of the research center.

An inspection conducted in 2016 by the World Health Organization revealed that Vector met biosafety and biosafety standards and had no safety concerns.