MANILA (Reuters) - Philippine President Rodrigo Duterte has approved a five-year plan to spend 300 billion pesos ($5.6 billion) to modernize the outdated military, defense officials said on Wednesday.

Philippine's President Rodrigo Duterte speaks during the 120th Philippine Independence day celebration at the Emilio Aguinaldo shrine in Kawit, Cavite Philippines June 12, 2018. REUTERS/Erik De Castro

A previous 15-year upgrade plan failed to take off in the mid-1990s, leaving the Philippines with outdated hardware, including warships from World War Two and helicopters used by the United States in the Vietnam War.

“We have the go signal now to buy brand-new equipment, like fighters, drones, light tanks, radar, an additional frigate and a submarine to boost our defense capability,” said a defense official, who declined to be named because he is not authorized to speak to media.

The previous administration of Benigno Aquino spent about $1.7 billion on the military during its 2010-2016 term in office, mostly on secondhand ships and planes.

Duterte approved the $5.6-billion modernization plan at a meeting with top defense and military officials last month.

A senior general said Duterte had approved 33 modernization projects, with a focus on domestic security and protecting the vast maritime borders of the archipelago nation.

“We’re putting a premium on unmanned aerial vehicles, long-range patrol aircraft, offshore patrol ships and an electric-diesel submarine,” he told Reuters.

The military is bent on preventing another Islamic State-inspired insurgency after rebels seized Marawi, the country’s only Islamic city, for five months last year.

The Philippines also faces a challenge in South China Sea, a strategic waterway most of which is claimed by China, which has built military outposts there.

Besides the Philippines, Brunei, Malaysia, Taiwan and Vietnam also have rival claims on the area, through which $3 trillion worth of sea-borne goods pass every year.

Manila had planned to acquire four submarines after 2023, but the plan could be accelerated to boost the navy’s regional capabilities, said Arsenio Andolong, a defense department spokesman.

“We want to get submarines as soon as possible,” he said.

Duterte had set aside $1 billion for new helicopters and light tanks, but no purchases have been made yet.

The Philippines has received donated military hardware from Australia, China, Japan, Russia and the United States, mostly to assist in disaster response and fighting militants and pirates.