Philippines' President Rodrigo Duterte, left, greets Vietnamese Prime Minister Nguyen Xuan Phuc as they meet at Phuc's Cabinet Office in Hanoi on September 29, 2016.
Philippines' President Rodrigo Duterte, left, greets Vietnamese Prime Minister Nguyen Xuan Phuc as they meet at Phuc's Cabinet Office in Hanoi on September 29, 2016.

HANOI/MANILA - Philippine officials were awaiting clarification Thursday from President Rodrigo Duterte about military exercises with U.S. forces after he promised to honor their defense treaty but declared joint war games would cease.

The maverick former Philippine mayor famous for his unpredictability and terse rhetoric, Wednesday told Filipinos in Vietnam that joint marine drills would be the last.

His remarks gave one of the clearest signs yet of his willingness to test the limits of a historic alliance that has provided important defense support for the Philippines and helped the United States further its Asia rebalance strategy in the face of an assertive China.

Visiting Vietnam's leadership Thursday, Duterte did not speak to media, but his foreign secretary, Perfecto Yasay, said longstanding treaties with the United States would be honored. 

Philippines President Rodrigo Duterte, left, and V
Philippines President Rodrigo Duterte, left, and Vietnam's Communist Party General Secretary Nguyen Phu Trongt talk at the party's headquarters in Hanoi, Vietnam, September 29, 2016.

He said exercises with U.S. forces planned for 2017 would go ahead because the previous government agreed to them, while those from 2018 and beyond would be reviewed. 

Yasay said the Philippines did not want a military ally and sought diversified relations and no enemies. 

The United States embassy in Manila said it had not received any official notice from the Philippine government on the termination of joint exercises. Philippine foreign ministry spokesman Charles Jose said it was possible that a Visiting Forces Agreement between the Philippines and the United States could be abrogated, but that would be up to Duterte.

The Department of National Defense said it is seeking guidance from the president. 

"The DND will await further orders from President Rodrigo R. Duterte," it said in a statement, adding its defense secretary would "seek more clarification and guidance."

"As stated earlier, all agreements and treaties with the U.S. are still in effect," it said in a statement. Yasay said Duterte's ruling out of joint maritime patrols with the United States had been misinterpreted, and he was referring only to exercises in waters disputed by the Philippines and China.

While railing at the United States, the country's biggest foreign investor, almost on a daily basis, Duterte has spoken warmly of China and the need to improve relations damaged earlier in the year by an international tribunal that rejected China's expansive claims in the South China Sea.

Duterte's snubbing of the United States and outreach towards China has added to uncertainty over his foreign policy, which has often been articulated via threats and expressions of a desire for peace.

His visit to Vietnam comes at a time when both countries are undergoing military modernization programs. The Southeast Asian neighbors agreed to a strategic partnership last year, in response to China's more vigorous maritime presence.

Former Philippine foreign secretary Albert del Rosario, who initiated the Philippines' successful arbitration case against China's maritime claims, said the Duterte administration should consider rethinking its approach.