The swiftness with which a landmark maritime treaty between Singapore and Indonesia was concluded underscores the deep strategic trust between the two countries, Foreign Minister Vivian Balakrishnan said yesterday.
The treaty, which is now in force, demarcates maritime boundaries in the eastern part of the Strait of Singapore.
Yesterday, Dr Balakrishnan and his Indonesian counterpart Retno Marsudi exchanged ratification instruments for the pact in a ceremony at the Foreign Affairs Ministry.
After the event, Dr Balakrishnan said at a joint press conference: "Without trust, you cannot make progress, especially on delicate and sensitive issues like sovereignty."
This is one of the fastest such treaties that Indonesia has concluded, Ms Retno said.
The treaty was inked in 2014, and covers a 9.5km stretch in the Singapore Strait between Changi and Batam.
It is the third of its kind between the two neighbours.
They first agreed on the maritime boundary along the central part of the Singapore Strait in 1973, and in 2009 signed another pact on the western section, between Indonesia's Pulau Nipa and Singapore's Sultan Shoal.
With the latest treaty in place, the three account for a continuous 67.3km-long sea border in the Singapore Strait.
Dr Balakrishnan said: "This has been a major testament to our ability to amiably resolve complex bilateral issues, and to do so through negotiations, and in accordance with international law."
One outstanding stretch remains to be demarcated between Pedra Branca and Bintan.
But it will have to wait for talks between Singapore and Malaysia on maritime boundaries around Pedra Branca, Middle Rocks and South Ledge.
Ms Retno, who was in Singapore at Dr Balakrishnan's invitation, said the two of them discussed a wide range of issues earlier in the day, including ways to boost cooperation in areas such as the economy and countering terrorism.
They also followed up on developments from Indonesian President Joko Widodo and Prime Minister Lee Hsien Loong's Leaders' Retreat in Semarang last year, such as the setting up of the Indonesia-Singapore Business Council.
The Kendal Industrial Park, which was launched during the retreat, has drawn interest from 27 companies, whose potential investments will exceed US$330 million (S$467 million).
Ms Retno and Dr Balakrishnan also discussed Asean, which turns 50 this year. Both countries have a shared aim of strengthening Asean unity and centrality.
Ms Retno said: "Asean has been central in contributing to peace, stability and prosperity in the region and beyond, and Indonesia is very committed to keeping it this way."
Yesterday, the two foreign ministers also announced the start of celebrations to mark 50 years of diplomatic ties between their countries. The celebrations will be known under the name RISING50, with a logo designed jointly by both nations.
There will be a slew of events to celebrate the multi-faceted relationship, paying tribute to cultural and historical links as well as budding areas of economic cooperation such as the digital economy. The planned activities include cultural performances and film screenings.
The events will be announced in due course, said Dr Balakrishnan.
Later this year, Mr Lee will host Mr Joko at the Leaders' Retreat in Singapore.
