United States President Donald Trump on Wednesday ignored the decision of Philippine President Rodrigo Duterte to terminate a decades-old military partnership with the US, stressing that he did not really mind it at all.

The US said the Philippines' decision to end their 22-year military accord was "unfortunate" as it tries to strengthen its foothold and compete with China in the Asia-Pacific region.

Terminating the 1998 Visiting Forces Agreement - which outlines the conditions for joint military exercises and engagement of US troops in the archipelago - marks the first concrete determination by the Philippine government to sever its defense cooperation with the Americans.

The outspoken Philippine leader announced the scrapping of the two-decades old VFA late Tuesday, a decision US Secretary of Defense Mark Esper called "a move in the wrong direction" as Washington and its allies pressure China to adhere to "international rules" in Asia.

The American consular office in Manila labeled the decision as a "serious step with significant implications." The president's decision, triggered by the cancellation of a US visa held by a former police general who spearhead Duterte's war on drugs, takes effect in 180 days and US officials have expressed optimism Duterte will change his mind.

In a White House media briefing, Trump said he does not really mind if that's what Duterte likes to happen, adding that "it will save us a lot of money."

Trump pointed out that the US had helped the Philippines fight and defeat the Islamic State militants. He also shared that he had a "very good relationship" with Duterte. "We'll see what happens next," Trump said.

The decision underscores a major shift that Duterte had signaled since he took office in 2016 as he refocused his foreign policy toward China.

The US and the Philippines signed a mutual defense agreement in 1951, which binds the two countries to defend each other in case of foreign aggression.

In a speech at the Malacanang Palace on Tuesday, Duterte said "Trump and the others are trying to save the VFA," but he addied that he doesn't want it anymore, an official transcript showed.

Terminating the VFA could also hurt the US' future military presence in the Asia-Pacific region in the midst of tensions over the presence of American servicemen in South Korea and Japan as well as security worries about North Korea and China.

According to Foreign Affairs Sec. Teodoro Locsin, the Philippines may find it very hard to access millions of dollars worth of military support, and trade links may also be jeopardized once the aggeement with the US is scrapped.

Joint military activities between the two countries -- including training for thousands of Philippine and American troops -- will also be greatly affected, Locsin added.