One boat carrying 50 people sank off early Thursday while the second boat carrying around 400 passengers sank off latter, reported BBC.
According to media reports, around 200 people have been rescued while coastguard officials continued rescue to fish out more bodies.
The victims of boat tragedy included migrants from Syria, Bangladesh and several sub-Saharan African countries.
According to UN, about 2,400 migrants have died trying to cross the Mediterranean to Europe so far this year.
On Wednesday, the bodies of at least 51 people were found in the hold of a stricken ship off Libya's coast.