Malacañang is set to issue a written order on the possible suspension of classes on September 21 despite President Duterte's announcement that the date is not a holiday.

Palace Communications Secretary Martin Andanar said it is clear that Duterte has declared September 21, the 45th anniversary of the declaration of the Marcos-era martial law, as a "national day of protest."

He added there is a need for a written order if the Palace is suspending classes or government work on the said date.

"Kailangan pong linawin ito sa pamamagitan ng order kung ito ba ay Metro Manila, kung ito ba ay nationwide...Within this day malalaman natin kung ano yung klarong order, kung may pasok ba o wala yung mga pampublikong paaralan. Yung ating mga opisina sa gobyerno," he told radio DZMM.

He said government workers can join protests on the date.