MANILA - President Rodrigo Duterte on Friday slammed the United States after one of its defense officials said the Philippines' plan to acquire submarines and other military equipment from Russia is unhealthy for its alliance with Washington.

“Is that the way you treat an ally and you want us to stay with your for all time? Who are you to warn us?” Duterte said in a speech in Davao City.

While on a visit to Manila, US Assistant Secretary of Defense for Asian and Pacific Security Affairs Randall Schriver had warned the Philippines against acquiring military hardware from Russia, one of Washington’s rivals.

According to Schriver, when a country buys weapon systems, “you’re not just buying capability, you’re investing in a relationship.” The US has been a primary source of military equipment for the Philippines, being a long-standing ally.

• US defense official warns PH on buying Russian military equipment

Schriver’s statement did not sit well with Duterte, who has long been harboring a grudge against the United States and has turned to Russia and China for aid.

Duterte said the Philippines must buy submarines if it wants to catch up with its neighbors in the military front.

“You state your case why you are against my country acquiring submarines. You want us to remain backwards?” he said.

Defense Secretary Delfin Lorenzana earlier said Moscow offered to provide the Philippines diesel-electric Kilo-class submarines.

The President also slammed the US for giving the Philippines, its treaty allies, merely refurbished military hardware.

He also revived his claim that the US Central Intelligence Agency is out to kill him.

“If my helicopter blows up, it’s them,” he said.