Prime Minister Hun Sen encouraged leaders of the Association of Southeast Asian Nations (Asean) to increase trade activities for the sake of regional development and prosperity at a summit in Thailand over the weekend.

Meanwhile, Cambodia’s minister of foreign affairs and international cooperation has said Asean was making efforts to ensure that the South China Sea remains a “sea of peace”.

Hun Sen returned to Cambodia after having attended an Asean summit in the Thai capital Bangkok over Saturday and Sunday.

He said after his return on Sunday that Cambodia respected the principles and duties as set by Asean, especially regarding its contribution to protecting security, development and prosperity.

The two-day summit looked at the core problems facing Asean, the strengthening of its capacity, especially contributions to reducing the development gap within the bloc, and trade in the region, Hun Sen said on social media.

Asean leaders also encouraged the association to respond to climate change and the environment, particularly managing the plastic waste plaguing the coasts of its member nations.

The leaders exchanged views on the challenges of climate change management and encouraged the bloc’s members to strengthen solidarity, particularly regarding cooperation on the economy, trade, investment and tourism, Hun Sen said on Facebook.

Cambodia also respected the principles regarding the creation of the Asean Regional Mine Action Centre (ARMAC), which has its headquarters in Cambodia.

Hun Sen also met with Singapore’s Prime Minister Lee Hsien Loong on the sidelines of the summit. Both agreed that the two countries would strengthen cooperation and “friendship”.

In late May, Lee sparked controversy when he said Vietnam had invaded and occupied Cambodia in 1979, with the late former Thai prime minister Prem Tinsulanonda on the “frontline” to face Vietnam and oppose its “occupation” internationally.

However, during their meeting on Sunday, Hun Sen and Lee reached common ground by regarding the recent row as “a very short bad dream in our diplomatic relations”, according to CNC TV, which accompanied Hun Sen on his trip.

Foreign minister Sokhonn said both leaders accepted they had different views on history and no one could change people’s perspectives on the past.

“But what is important is to keep the past like an old wound. We do not open it because it would hurt [us] again,” Sokhonn said, adding that both countries had agreed to move forward on a positive path.

At the summit, Sokhonn attended the Asean Foreign Minister’s Meeting, the 19th Asean Political Security Community and Council Meeting, and the 23rd Asean Coordinating Council Meeting.

“On Asean community-building, Prak Sokhonn emphasised the importance of the vision reflecting ways in which Asean can progress and prosper based on a sustainable partnership,” the Ministry of Foreign Affairs said.

With regard to the South China Sea, Sokhonn reiterated that Asean was on the right track in ensuring it remained a “sea of peace”.

“Asean and China should continue to work together closely to ensure the building of trust and confidence in making substantial headway towards the conclusion of an effective [Code of Conduct on the sea], a ministry statement stated.

Sokhonn said it was of paramount importance that Asean and China continued to uphold the “Bali-Siem Reap Spirit”, which came about after meetings in the two locations in early 2017 and emphasises flexibility and mutual compromise.

“On terrorism and transnational crimes, Prak Sokhonn underlined Cambodia’s commitment to working with other Asean member states to combat terrorism in all its forms and manifestations,” the ministry said.