MANILA, Feb. 12 (Xinhua) -- The spokesman of Philippine President Rodrigo Duterte said on Wednesday that Manila's move to terminate the Visiting Forces Agreement (VFA) between the Philippines and the United States "is in the right direction."

From the point of view of the Philippines, presidential spokesman Salvador Panelo said the decision to terminate the VFA "is a move in the right direction that should have been done a long time ago."

The Philippine government on Tuesday officially notified the U.S. government about Duterte's decision to scrap the VFA that allows the U.S. forces to take part in large-scale joint military exercises with Philippine troops.

Duterte decided to scrap the VFA after the U.S. cancelled the visa of Senator Ronald Dela Rosa, his longtime aide, over Dela Rosa's role in the war on drugs during his term of Philippine National Police chief.

"I think the cancellation of Senator dela Rosa's visa was the immediate trigger," Lucio Blanco Pitlo, the Research Fellow on international relations at the Philippine think tank Asia-Pacific Pathways to Progress Foundation, told Xinhua.

Specifically, Duterte was angered by the U.S. lawmakers' demand to free detained Senator Leila De Lima, who has been detained over drug-related charges since February, 2017.

"The visa cancellation was taken by Duterte as an affront to one of his key domestic policies which is the anti-drug war and an interference in the Philippine justice system as there is an ongoing case related to the detention of De Lima," Pitlo said.

"I suppose he wants to send a strong message of displeasure against what he sees as persistent foreign interference in the country's domestic affairs," Pitlo added.

Pitlo said Duterte's actions also fit with his foreign policy which is to distance his administration from the United States.

Spokesman Salvador Panelo said on Wednesday that reliance on another country for his own country's defenses against the enemies of the state will ultimately weaken and stagnate its defense mechanisms.

"We must stand on our own and put a stop to being a parasite to another country in protecting our independence and sovereignty," he said.

"It is about time that the Philippines strengthen our defense capabilities," Panelo added.

He said, "Our studied action is consistent and pursuant to our chartering an independent foreign policy, with our foreign relations anchored solely on national interest and the general welfare of our people."

Panelo has said the termination will take effect 180 days later and will not need U.S. concurrence.

U.S. Defense Secretary Mark Esper said on Tuesday that Manila's withdrawal from the VFA "would be a move in the wrong direction."

Panelo slammed Esper for making such a statement, saying the U.S. defense chief's commentary "is expected given that the VFA favors the U.S. and its abrogation affects its global strategic defensive positioning."

Pitlo said the Philippines-U.S. relations "will certainly experience turbulent times" under Duterte's term which ends in 2022. "The military-to-military ties will be seriously affected if VFA will be terminated," Pitlo warned.

U.S. State Assistant Secretary for Political-Military Affairs R. Clarke Cooper said on Monday that the U.S. has about 300 engagements and exercises that the U.S. forces conduct bilaterally with the Philippines.

Asked what is at risk without a VFA, Cooper said, "Well, without a VFA, it puts at risk things like these engagements, like these exercises."

The Philippines and the U.S. signed in 1998 a VFA allowing joint Philippine-U.S. military operations. The Philippine senate ratified the agreement in 1999, seven years after the closure of the last U.S. base on Philippine territory.

When Duterte came to power in 2016, he vowed to scrap the VFA and the Enhanced Defense Cooperation Agreement (EDCA) with the U.S. and chart an independent foreign policy.