Argentina's President Cristina Fernandez (C) visits the site of a building explosion in Rosario City, around 300 km away from Buenos Aires city, capital of Argentina, on Aug. 7, 2013. A strong explosion shook buildings in northeastern Argentina Tuesday morning, killing at least 10 people and injuring more than 60 others, local authorities confirmed. The government of Argentina Wednesday declared two days of national mourning for the 10 fatal victims of an explosion in an apartment building in the northern city of Rosario.