TTC special constables will be walking their beats "with increased vigilance" today following a deadly subway bombing in Moscow.

Danny Nicholson, the TTC's supervisor of corporate communications, said the organization does not believe that there is any specific threat to Toronto commuters, but the special constables will be on alert nonetheless.

Moscow's subway system was hit by two suicide blasts during the Monday morning rush hour, which killed 37 people and injured dozens of others. Russian officials believe rebels from the Caucasus region are responsible.

In New York, the Metropolitan Transportation Authority beefed up its security Monday after what happened in Russia. A spokesperson said the New York transit agency had a "heightened security presence," but did not provide any further details.

Authorities in London and Madrid -- two European cities that have suffered attacks on their own subways -- said there were no immediate plans to increase security.

With files from The Associated Press