MANILA - Some 20,000 people wearing black shirts will gather at sundown in the capital's main park on Friday to protest former president Ferdinand Marcos' burial at the Libingan ng mga Bayani (Heroes' Cemetery), a rally organizer said.

Victims of human rights abuse and veteran figures who led the fight against the Marcos dictatorship will join students in Luneta in what is hoped to be the first of many mass actions against the interment, which was approved by President Rodrigo Duterte.

"This is going to be much bigger than what we've seen in recent months because institutions that do not traditionally send protesters are joining," Campaign Against the Return of the Marcoses to Malacañang (CARMMA) convenor Bonifacio Ilagan told ABS-CBN News.

Ilagan said all schools along the university belt in downtown Manila would send contingents to the "Black Friday" protest.

Marcos was buried in a surprise, closely-guarded ceremony last week, sparking outrage among groups who accuse him and his family of stealing up to $10 billion from state coffers.

Former senators Rene Saguisag and Bobby Tanada are expected to join the protest, while "surprise celebrities and guests" will provide entertainment during the program, Ilagan said.

"Our protests are aimed at the reversal of the burial and for President Rodrigo Duterte to once and for all abandon his alliance with the Marcoses," Bagong Alyansang Makabayan Secretary General Renato Reyes said.

"The people hold Duterte accountable for the burial. The people likewise demand an end to a system of political accommodation and compromise among the elite," he added.

Police said maximum tolerance would be observed.

"Pabayaan namin sila. Sa kanila na yang mga plaza, mga kalsada kung gusto nila. Hindi na namin sila pakialaman," Philippine National Police Chief, Director General Ronald Dela Rosa, said Thursday.

(We will let them do what they want. They can occupy the plaza and the streets if they want. We will not meddle with their affairs.)

In a separate interview with ANC's Dateline Philippines, Ilagan said he is still uncertain what the future holds, but Friday's demonstration will definitely not be the last.

"This, the second ‘Black Friday Protest,’ I think this is going to be the second in a series of protest actions—maybe not necessarily every Friday, but this is definitely going to continue," he said.

"Ang laban ngayon ay laban na para sa isip at damdamin ng taongbayan, and we know that the protests are going to happen not only in the National Capital Region, but in so many urban and towns all over the Philippines—Luzon, Visayas, and Mindanao," he added.

(Today's fight is a fight for the people's minds and hearts, and we know that the protests are going to happen not only in the National Capital Region, but in so many urban and towns all over the Philippines—Luzon, Visayas, and Mindanao.)