Russian authorities say construction workers in Moscow have found the remains of at least 34 people who may have been killed during the brutal dictatorship of Joseph Stalin.

Workers restoring a 19th century building found the skeletons and a rusted pistol Wednesday under a basement floor.

Moscow city police examining the scene say the remains appear to date back to the 1930's, and the skulls indicate some of the people had been shot in the head.

However, Russia's Itar-Tass news agency quotes a spokesman, Sergei Baluchevsky for the regional prosecutor's office as saying no signs of forcible death have been found on the skeletons, and it is not clear when or how the people died.

Experts say the 34 people whose remains were found were probably victims of Stalin's security police who carried out a vicious campaign of political killings in the late 1930's that became known as the "Great Terror."

Historians estimate agents killed more than 800,000 people of 1.7 million arrested during the Great Terror, which reached its height in mid-1937.

The building in question is located on a main street connecting Russia's Soviet-era KGB security service headquarters to Red Square.

Russian media reports say efforts are under way to identify the 34 skeletons.

Some information for this report was provided by AP and Reuters.