The site of the blast is about 100 meters from the town hall in Cangas.
It destroyed a real estate office in the ground floor of a building and also caused damage to nearby buildings, the Interior Ministry office in the regional capital, A Coruna, said.
Bomb disposal experts from the police cordoned off the site as they searched for traces of the explosive.
Putin's official spokesman Dmitry Peskov commented on remarks in the US media about failures in launching nuclear-capable missiles in Russia
The Buk system that shot down MH17 belonged to the 53rd SAM missile brigade of the Russian Ministry of Defense, investigators say after looking at a few pictures on the net
It has long been understood that the West has been trying to subject Russian borders to total control. We have not seen such activity even during the Cold War