President Rodrigo Duterte returned Saturday morning from an official visit to Brunei Darussalam where he attended the golden anniversary of the accession of Sultan Hassanal Bolkiah to the throne.

Duterte arrived in Davao at 1:45 am, the Palace said.

"The President personally conveyed his warm greetings to His Majesty the Sultan of Brunei on the occasion of the golden anniversary of his accession to the throne, " said Presidential Spokesperson Ernesto Abella in a statement Saturday.

Duterte joined heads of state and government in celebrating the ocassion.

"The President also reaffirmed the long and enduring ties between the Philippines and Brunei Darussalam and renewed the special friendship between the two countries," he added.

Bolkiah has been supporting the peace process in Muslim Mindanao, which is still gripped by a nearly five-month battle between the military and Islamic State-inspired militants in Marawi City.

"The president has described His Majesty the Sultan as a friend of the Philippines in the truest and most profound sense of the word; he also recognizes His Majesty the Sultan's principled commitment to the pursuit of just and lasting peace and development in Mindanao, the well-being of Filipinos in Brunei Darussalam, and his unequalled efforts to bring the two countries closer to each other," said Abella.

Bolkiah had a state visit to the Philippines last April 27 ahead of the 30th Association of Southeast Asian Nations Summit.

"The president looks forward to further broaden and deepen bilateral cooperation with Brunei Darussalam, as well as to advancing efforts toward a more peaceful, prosperous and progressive ASEAN," said Abella.

Brunei has also become a "second home to 23,000 Filipinos" who are working in the oil-producing country. DMS