At the time, Duterte said, "I'm no American puppet," and suggested Manila would turn to Russia instead.

The trip, alongside recent visits to China, is designed to diversify the Southeast Asian nations' trade as relations with allies such as the European Union and the US become increasingly chilly.

Russian President Vladimir Putin extended the invitation on the sidelines of an APEC summit in Peru last November, according to Maria Natividad, Philippines' assistant secretary for foreign affairs.

The trip sends "a strong message of the Philippines' commitment to seek new partnerships and strengthen relations with nontraditional partners" such as Russia, Natividad said.

The visit to Moscow and St. Petersburg marks the first time Duterte will visit Russia and his administration hopes it will "mark a new chapter in Philippine-Russia relations," she added.

It will kick off with a bilateral meeting between Duterte and Prime Minister Dmitry Medvedev, before the Philippines' president gives a policy speech at the Moscow State Institute of International Relations (MGIMO) on the Philippines' independent foreign policy and "his ideas on how to achieve peace and security, especially in the Asia Pacific region."

He will then meet Russian President Vladimir Putin -- who Duterte previously described as his "favorite hero" -- before hosting a gathering of expatriate Filipinos who have settled in Russia and surrounding countries.

The two countries last year marked 40 years of diplomatic relations, but ties remain "best described as cordial albeit modest in scope and depth," Natividad said at a pre-departure briefing for the press ahead of the trip.

The trip, which a trade delegation will also attend, is expected to lead to deals in defense, security, legal assistance, tourism, the "peaceful use of nuclear energy" and cultural exchange.

Bilateral trade in 2016 totaled $226 million, with the Philippines only exporting $49 million worth of goods to Russia, Natividad said.

Western countries have taken issue with Duterte's track record on human rights since taking office -- his police force has waged a bloody war on drugs over the past year, with extrajudicial killings of dealers and users numbering the thousands.

"They're blackmailing me that they won't sell weapons? We have lots of explosives here," Duterte said, according to CNN Philippines.

"I remember what the Russian diplomat said: Come to Russia, we all have here anything you need."

The Philippines has also distanced itself from the European Union, recently rejecting an aid package worth around 250 million euros ($278 million) over the next three years, given as it was tied to commitments to improve human rights.

"We cannot accept aid with conditions," Foreign Affairs Minister Alan Peter Cayetano said.

"We're just telling them very respectfully: we believe in our independence. We know our problems better than you. You are welcome here. Let's do business but we will not accept aid if there are conditions or you will interfere."

Kurlantzick suggested that while Duterte is likely to visit Washington he may not want to appear as though he is embracing the US, given how much he has courted China and Russia.

CORRECTION: A previous version of this story incorrectly identified the title of Maria Natividad. She is the Philippines' assistant secretary for foreign affairs.