State Senate Republicans unveiled a legislative plan yesterday that would toughen penalties for the sale, possession and use of illegal guns.

The package, which singles out possession on school grounds and school buses and would put killers of on-duty emergency responders in prison for life without parole, places the GOP at loggerheads with Gov. Cuomo and his push to ban assault weapons.

Cuomo spokesman Josh Vlasto said failing to “ban assault weapons ignores the reality of gun violence and insults the common sense of New Yorkers.”