MANILA (1st UPDATE) – President Rodrigo Duterte needs advice on the "art of diplomacy," after his fiery rhetoric led to the cancellation of a meeting with US President Barack Obama, the Philippines' former envoy to the United Nations (UN) said Tuesday.

The US snub, however, is a "mere blip" in the long-standing ties between the two treaty allies. Manila can seek to reschedule the meeting, but if Washington refuses, it should "move on," former ambassador Lauro Baja said.

"I think the President should be advised on the art of diplomacy and the implications of the strategic importance of approaches to the intricacies of international relations," Baja told ANC.

"The onus is on his advisers," he added.

Duterte's toned-down rhetoric just hours after threatening to curse at Obama if he brings up his bloody war on drugs during their meeting is "too late," Baja said.

"It's unfortunate. Meetings between heads of state is the highest form of diplomacy. That's an opportunity missed," he said.

In an interview on DZMM TeleRadyo, Baja said he hopes that the two leaders will be able to have an opportunity to meet "even in the meeting rooms or corridors" to shake hands and show that everything is all right between the two countries.

"May lamat na iyan, kahit na maling kaunti (Even a small mistake can put a crack in the Philippines’ relationship with the US),” he said. “That (positive interaction) will serve to cancel any negative implications."

However, he hopes Duterte realizes that he cannot expect the world to simply "accept en toto [his] character or zeal" as it will be the Filipino youth who will be dealing with other countries in future, and his words will also affect Filipinos living abroad.

Obama's response to Duterte's impassioned speech should serve as a model, he said.

"It was a very measured response. Let's move on. There are other bilateral [meetings] to attend to, and other issues to attend to in the summit."

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