An explosion believed to have been caused by an improvised explosive device (IED) occurred near the entrance of the Department of Justice (DOJ) compound in Manila early Monday, prompting authorities to tighten security hours before President Ferdinand Marcos Jr.'s State of the Nation Address.

The blast occurred at around 12:17 a.m. along Padre Faura Street in Ermita, the DOJ said.

Personnel from the Philippine National Police Explosive Ordnance Disposal (PNP-EOD) Unit responded to the scene to conduct a technical examination.

"The investigation is ongoing to determine the source, nature, and circumstances surrounding the explosion," the DOJ said in a statement.

The department said the situation is under control and the compound remains secure as authorities continue a comprehensive investigation.

Police also recovered an improvised explosive device near the Senate in Pasay City on Monday morning.

Authorities have yet to determine whether the two incidents are connected.

Elements of the Armed Forces of the Philippines National Capital Region Command were also deployed to help secure the DOJ compound.

DOJ spokesperson Atty. Polo Martinez said investigators are reviewing CCTV footage and other available evidence.

"The CCTV footage and other available evidence relating to the incident at the DOJ are currently being reviewed by the relevant law enforcement and security authorities as part of the ongoing investigation. Updates will be provided when appropriate," Martinez said.

He added that the explosion caused slight damage to a parked Toyota Innova, but stressed that the DOJ has taken the necessary measures to ensure the safety of its personnel and the public while maintaining uninterrupted operations.