While the statement issued by the joint ASEAN-Japan summit on Saturday did not specifically mention any country, the phrase "freedom of overflight" is understood as an implicit reference to China's recently established air defence identification zone. The statement said the ASEAN and Japan have agreed to strengthen cooperation regarding air and maritime linkages, and to recognise the benefits of enhanced connectivity among the countries.
The countries will "enhance cooperation in ensuring the freedom of overflight and civil aviation safety in accordance with the universally recognised principles of international law", it said.
At the summit and on its sidelines, Japanese Prime Minister Shinzo Abe sought to generate an understanding of Japan's position on China's ADIZ among the ASEAN countries.
But not all leaders shared his view.
Brunei's Sultan Hassanal Bolkiah said on Friday - the opening day of the summit, which ends on Sunday - that the issue should be resolved through consultations between Japan and China.
Lu Yaodong, director of the Japanese diplomacy department of the Institute of Japan Studies under the Chinese Academy of Social Sciences, said China's Southeast Asian neighbours - most of which have strong relationships with China - hope conflicts between China and Japan will be resolved.
"The growing antagonism between Tokyo and Beijing actually doesn't serve their interests," Lu said.
"They have their own opinions on relevant issues."
Japanese diplomats had been negotiating with their ASEAN counterparts to include a sharp reference to China's ADIZ in the joint statement.
Abe succeeded in getting his proposed language about a "proactive contribution to peace" incorporated into the statement.