The Philippines' government has informed the Pentagon that it has suspended joint naval patrols with the U.S. military in the disputed areas of the South China Sea.
Philippine Defense Minister Delfin Lorenzana told reporters Friday he informed the commander of the U.S. military's Pacific Command of the decision to halt the missions, which were launched this year to send a message to China.
"They know it already," he said of U.S. officials. "There is no patrol in the South China Sea."
The patrols were part of President Obama's plan to shift U.S. focus from the Middle East to East Asia, a strategy often termed his "Asia pivot."
China in recent years has made aggressive territorial claims after building artificial islands off the mainland's southern coast, sweeping east of Vietnam, down near Malaysia and Brunei, and then looping back up west of the main Philippine islands.
The Philippine government has worried that such claims could lead China to assert full sovereignty and control over all the land, water and air in the area, so U.S. and Philippine naval ships have passed through the area on multiple times this year as a show of strength.
"We take note of Secretary Lorenzana's public comments, and will be seeking clarification through direct dialogue," Pentagon spokesman Cmdr. Gary Ross said in a statement. "We will continue to consult closely as we always have with our Filipino partners to appropriately tailor our assistance."
It is the first concrete example of the Philippines backing up the words of recently elected President Rodrigo Duterte, who this week said that President Obama could "go to hell" and that he "lost … respect for America," before threatening to completely break ties with the United States.
Last month, Duterte called Obama a "son of a bitch" in Tagalog.
The relationship between the nations soured after Obama criticized Duterte's violent crackdown on drug cartels, dealers and users.
Rodger Baker, who leads Asia Pacific analysis for the global intelligence company Stratfor, said the Philippine government's comments "could be more than bluster, at this point."
"The Philippines could be angling for closer ties to China," he said. "It's a big risk, but they may think they have something more to gain here."
Until Duterte took office for his six-year term on June 30, the U.S. and Philippines were believed to have a strong alliance. Washington and Manila have had a mutual defense treaty since 1951.
Just this week, hundreds of U.S. Marines and sailors practiced amphibious landings and other joint exercises with Philippine troops at several coastal locations between Luzon and Palawan.
The exercise, one of 28 such annual exercises, began Tuesday and are scheduled to run until Oct. 12. But Duterte said last week it would be the final round of joint exercises with the U.S. military.
Under the Enhanced Defense Cooperation Agreement, which has been criticized by Duterte, the U.S. has access to Philippine military bases in exchange for providing maritime security and humanitarian aid during emergencies.
The deal was initially signed April 28, 2014, and upheld as constitutional by the Philippine Supreme Court on Jan. 12, 2016.
The Pentagon said about 300 to 500 troops are in the Philippines to support regular bilateral training, exercises and activities.
In addition, the number of U.S. special forces in the Philippines ranges from 50 to 100, and they provide advice and assistance against Muslim extremists in the southern part of the country. Lorenzana on Friday dismissed their importance.
"All they do is operate their drones and some intelligence equipment to help our troops in the south," Lorenzana said.
He added, "President Duterte said he doesn't want them to leave immediately but maybe in the future" — after the Philippines is able to operate its own drones.
"We think comments like this, whether they are or will be backed up by actual action or not, are really at odds with the closeness of the relationships that we have with the people of the Philippines," State Department spokesman John Kirby said Friday in Washington.