Philippine President Rodrigo Duterte will end the Visiting Forces Agreement that underpins U.S. military training exercises with the country's troops, one of his top advisers announced Friday.

“The president said he is terminating the VFA,” Philippine Defense Secretary Delfin Lorenzana said on Friday. “I asked for clarification, and he said he is not changing his decision.”

That choice is another blow to the relationship between the United States and the Philippines, which has suffered for years from disputes over Duterte’s human rights record. The belligerent president announced a plan to terminate the deal, which provides legal protection to U.S. troops who visit the island for military drills, after the State Department reportedly canceled the visa of a political ally and former police chief who is suspected of involvement in extrajudicial killings.

"I'm warning you ... if you won't do the correction on this, I will terminate the ... Visiting Forces Agreement,” Duterte said late last month. “I'll end that son of a bitch.”

Lorenzana argued against scrapping the agreement in a legislative hearing on Thursday, emphasizing that the pact is “more beneficial” to the Philippines “compared to any benefits” that might seem to come from ending it.

"Our contribution to regional defense is anchored in our military alliance with the world's last superpower,” he told lawmakers.

Any weakening of the U.S.-Philippine alliance is a cause for celebration in Beijing, as U.S. officials believe that China is pursuing a plan to dominate the Indo-Pacific region and ultimately challenge the U.S. as a global power.

The Philippines have an important role to play in countering that effort because they are one of the countries with the legal standing to contest China’s claim to sovereignty over the South China Sea, a vital international shipping lane.

The end of the Visiting Forces Agreement would not scuttle the U.S. alliance with the Philippines immediately, as the two nations are bound by a Mutual Defense Treaty and an Enhanced Defense Cooperation Agreement. Secretary of State Mike Pompeo affirmed Washington’s commitment to those pledges last year.

“China’s island-building and military activities in the South China Sea threaten your sovereignty, security, and therefore economic livelihood, as well as that of the United States,” Pompeo said in Manila. “We remain committed to supporting not only the Philippines in that effort — and the Philippines will need to do its part as well — but all the countries in the region so that these incredibly vital economic sea lanes are open and China does not pose a threat to closing them down.”

That relationship has been undercut by Duterte’s drug war, a campaign that is central to his political identity but that he has prosecuted with a brutal disregard for human rights, according to a recent State Department report.

“My only sin is the extrajudicial killings,” Duterte said in 2018.

The Philippine leader is taking aim at the 20-year-old Visiting Forces Agreement in defense of Sen. Ronald "Bato" dela Rosa, a former police chief who oversaw anti-drug operations that left at least 4,000 suspects dead over a two-year period. The visa cancellation “might be related” to his conduct as police chief, dela Rosa acknowledged at the time.

Lorenzana testified Thursday that he fears that the termination of the Visiting Forces Agreement might lead the U.S. to limit other military ties or cut various forms of financial aid to the country. Still, he struck a loyalist note after Duterte’s directive.

“The president, as the ultimate authority on foreign relations, has decided. And whatever he decides on this matter has my unqualified support,” the defense chief said. “What I think becomes irrelevant.”