Philippines' Foreign Minister Perfecto Yasay addresses the United Nations General Assembly in the Manhattan borough of New York, U.S., September 24, 2016. REUTERS/Eduardo Munoz

MANILA - The United States has "failed" the Philippines, prompting President Rodrigo Duterte to break the country's "shackling dependency" on its long-time ally, his foreign minister said Thursday.

Washington has for too long employed a "carrot and stick" approach "to force Filipinos into submission to American demands and interests," Foreign Affairs Secretary Perfecto Yasay said in a statement entitled "America has failed us."

Despite winning independence from the US in 1946, Yasay said Americans still regarded Filipinos as "little brown brothers not capable of true independence and freedom."

"This is what PRRD (Duterte) is now trying to liberate us from," he said.

"Breaking away from the shackling dependency of the Philippines to effectively address both internal and external security threats has become imperative in putting an end to our nation's subservience to United States' interests," he said.

Duterte told US President Barack Obama this week to "go to hell," the latest in a string of verbal attacks prompted by Washington's criticism of his bloody war on drugs.

He has also signaled an end to joint war games, casting doubts on the future of the two countries' military alliance.

The US is the Philippines' only treaty ally. The 1951 Mutual Defense Treaty binds the two countries to "defend themselves against external armed attack."

While criticizing the US, Duterte has signaled building ties with Washington's foes Beijing and Moscow. This despite the Philippines and China sparring over the resource-rich South China Sea.

In spite of its alliance with the US, the Philippines remains "grossly incapable" of defending its territory, Yasay said.

"Worse is that our only ally could not give us the assurance that in taking a hard line towards the enforcement of our sovereignty rights under international law, it will promptly come to our defense under our existing military treaty and agreements," he said.

A United Nations-backed court has ruled in favor of the Philippines and said China had no historic rights to the South China Sea.

Duterte has appointed former President Fidel Ramos to negotiate with China after the landmark decision.

Yasay acknowledged that the country had "serious concerns and challenges with the Chinese" because of the sea row.

"Our past mistakes in fostering and strengthening our friendship with our white big brother will be instructive for this purpose," he said.

"We will never allow China or any other nation to bully us or deal with Philippine interests under another carrot and stick policy," he added.