The fatalities are broadly in line with Friday's tally of 541, which was the second highest since the outbreak emerged on Feb. 21.
The number of cases in the region, which includes Italy's financial capital Milan, increased by some 2,117 to roughly 39,415 the source said.
On Friday there were 2,409 new cases.
The nationwide tally will be released at around 6.00 p.m.