Southeast Asian leaders agreed to work intensively toward an agreement by the end of this year on plans to create what could potentially be the world’s biggest trading bloc.

Attempts to advance the so-called Regional Comprehensive Economic Partnership were a key talking point at a summit of the Association of Southeast Asian Nations that concluded in Singapore on Saturday.

“We very much hope that we will be able to do it this year because otherwise events will supervene and there will be elections and the matter will fizzle out,” Singapore Prime Minister Lee Hsien Loong told reporters.

If ever fully achieved, the partnership would include the 10 Asean nations as well as China, India, Japan, South Korea, Australia and New Zealand, and cover one third of world’s economy and almost half its population.

While the pact doesn’t seek to impose higher standards in areas such as labor and environmental protection, like the 11-nation Comprehensive and Progressive Agreement for Trans-Pacific Partnership signed earlier this year, consensus is proving elusive.

A major obstacle is India’s requirement that any agreement to reduce tariffs on goods and services should allow for free movement of people, something India wants for its highly skilled information technology sector.

While Lee could not rule out the possibility that smaller groupings could emerge if an agreement is not reached soon, he said the current intention is to include all 16 nations.

South China Sea

Lee said negotiations to finalize a maritime code of conduct covering the disputed South China Sea, where Beijing’s territorial claims overlap with those of Asean members Malaysia, the Philippines and Vietnam, will take some time.

With differing views on whether the code should be legally binding, Lee said reaching agreement wouldn’t be easy. “But it’s better that we spend our time talking about the code of conduct constructively, trying to keep the temperature down than that we don’t try,” Lee said.

Lee said Asean leaders also received a briefing from Myanmar on the situation in Rakhine state where more than 600,000 Rohingya refugees have fled to neighboring Bangladesh since August.

“We encourage Myanmar and Bangladesh to press on with their shared commitment to carry out the voluntary return of displaced persons in a safe, secure and dignified way without undue delay,” Lee said.

Lee said Asean leaders welcomed the inter-Korean summit on Friday, which would contribute to peace and stability in the region, as well as plans for North Korean President Kim Jong Un to meet with U.S. President Donald Trump. Lee said Singapore hadn’t received any formal request to host the meeting.