Mikati's office in a statement said flags will be lowered at half-mast in all government departments, public institutions and municipalities.
The statement added that public offices will also close on the day of Nasrallah’s funeral. Hezbollah, however, has not yet announced the date for the funeral.
Israeli forces began large-scale airstrikes in Lebanon earlier this week, killing hundreds, and displacing thousands. Tensions escalated further after it killed Nasrallah and other commanders in Beirut on Friday. Israeli forces continued to bomb parts of the Lebanese capital on Saturday.