Hundreds of thousands of Filipinos, including about 650,000 members of the Iglesia Ni Cristo, gathered in Manila on Sunday for the largest rally yet demanding accountability for a flood-control corruption scandal.

Investigations revealed that thousands of flood defense projects were substandard or nonexistent, with lawmakers and public works officials allegedly taking kickbacks from construction companies.

Smaller protests also took place, including one in Quezon City attended by retired generals and other citizens.

Authorities deployed thousands of police and military personnel to secure the rallies, which remained peaceful despite past clashes at similar demonstrations, the AP has reported.

Protesters called for justice and the return of misappropriated funds, while the presidential palace and surrounding roads were placed on lockdown for security.