MANILA, Philippines (AP) — A massive fire tore through Manila’s historic post office building overnight, slightly injuring seven people and razing the nearly 100-year-old landmark in the Philippine capital, police and postal officials said Monday.

The fire started before midnight in the basement of the neoclassical, five-story building and was brought under control Monday morning more than seven hours after it began, firefighters said.

An investigation was underway to determine the cause of the fire and what was damaged, officials said, adding seven people, mostly firefighters, sustained minor injuries or were overwhelmed by thick smoke.

The Manila Central Post Office was one of the capital’s busiest office buildings but was closed when the fire started. The building was the country’s main mail-sorting and distribution hub and was the central office for the Philippine Postal Corporation.

Postal service in the Philippines began during the Spanish colonial period with horse-riding mail couriers.

The building, now recognized as a national landmark, was built in 1926 with high columns in the traditional neoclassical style. It was severely damaged during World War II and was rebuilt in 1946.

It is located along the Pasig River and on a main intersection of the capital's key roads.