MOSCOW, Sept. 27 (Xinhua) -- International exercises in countering nuclear terrorism started here Thursday, the Russian Federal Security Service (FSB) said.

According to a statement on the FSB's official website, Guard-2012 involved 58 countries, as well as observers from the International Atomic Energy Agency (IAEA), Interpol, and the United Nations Office on Drugs and Crime (UNODC).

The exercises, within the framework of the Global Initiative to Combat Nuclear Terrorism (GICNT), are aimed at demonstrating anti-terror measures.

The Russian Defense Ministry and state atomic agency Rosatom would demonstrate the country's latest technology for detecting nuclear materials and radioactive substances, the FSB said.

They would also put special relief units through their paces in dealing with a simulated aftermath of a nuclear terrorism attack, it said.

In 2006, the presidents of Russia and the United States jointly launched GICNT at the G8 summit in the Russian city of St. Petersburg.

GICNT is an international partnership of 85 nations and four official observers. Its mission is to strengthen international cooperation to prevent, detect, and respond to nuclear terrorism. The United States and Russia serve as co-chairs.