Philippine President Ferdinand Marcos Jr. could make a state visit to Japan early next year, likely before he makes a similar visit to China, his top aide said Monday, as Manila continues to bolster its defense cooperation with Tokyo amid Beijing's growing maritime assertiveness.

The president attaches "great importance" to visiting Japan, the biggest source of official development assistance for his country, Lucas Bersamin told Kyodo News in his first interview with foreign media as executive secretary, adding that "there's no urgency to go to China."

Marcos has already accepted China's invitation for a state visit. When asked if his trips to the two countries will occur at the same time, Bersamin said he expects the Japan trip to take place "early next year" and "ahead of China."

The adviser said Marcos is looking to Japan for continued collaboration in fields including clean energy, infrastructure, agriculture and food security, and maritime security in the South China Sea.

He said the president may ask for further assistance from Japan with regard to patrol boats, saying that "our coastlines will have to be defended."

The Philippines has a territorial dispute with China in the South China Sea, to which Beijing has laid sweeping claims. With only three large patrol ships in its fleet, including two provided by Japan in May and June, its coast guard remains outmatched by the better-equipped Chinese coast guard in the contested waters.

Marcos and Prime Minister Fumio Kishida first met in September on the sidelines of the U.N. General Assembly in New York, and arrangements have been under way for the Philippine leader's trip to Japan.

The visit was initially scheduled for December but pushed back due to regional and international conferences taking place later this year, Bersamin said.