Southeast Asian leaders on Wednesday condemned an armed attack on an aid convoy that the regional bloc had arranged for displaced people in Myanmar while calling for an immediate stop to violence and for the military government to comply with a peace plan. Leaders of the Association of Southeast Asian Nations convened in the picturesque harbor town of Labuan Bajo in southern Indonesia at the start of a two-day summit. The ASEAN said it is "deeply concerned" about the violence in military-ruled Myanmar as Indonesian President Joko Widodo called for "unity" among its 10 members, which are divided over how to handle the crisis. Myanmar military chief Min Aung Hlaing has all but ignored a five-point plan to end the violence. The plan was agreed at a special ASEAN summit two years ago, and violence has only intensified since. "We were deeply concerned with ongoing violence in Myanmar and urged the immediate cessation of all forms of violence and the use of force to create a conducive environment for the safe and timely delivery of humanitarian assistance and inclusive national dialogues," the leaders said in a statement after summit discussions on Wednesday. ASEAN, which admitted Myanmar as a member under a previous military regime, has been leading diplomatic efforts to end the bloodshed under the current military government, sparked by its February 2021 coup, but the bloc has little to show for it. The military's bombing of a village in the northern region of Sagaing last month killed dozens of people, and Human Rights Watch on Tuesday accused the armed forces of dropping a vacuum bomb. At the weekend, the crisis hit closer to home when a humanitarian aid convoy, including diplomats from Singapore and Indonesia, came under fire from unknown attackers as it travelled in Shan State in eastern Myanmar. "We condemned the attack and underlined that the perpetrators must be held accountable," the ASEAN statement said. Widodo, the current ASEAN chairman and host, expressed confidence the group would be able to work together to handle the issues it faces. Myanmar, although a member, is barred from the group's main summits. "Will ASEAN only be silent, or will ASEAN be able to become the driver or peace or growth?" Widodo asked. "I am convinced that we all believe ASEAN can do it only if there's unity." Since taking over ASEAN's rotating chairmanship, Indonesia has been quietly engaging Myanmar's military, armed ethnic groups and the National Unity Government (NUG), which includes elected MPs removed in the coup, to try to end the violence. "ASEAN is doing as much as it can really because when you are there on the ground, it's not that easy," Philippine Foreign Affairs Secretary Enrique Manalo said. But former Indonesian Foreign Minister Marty Natalegawa said it is time for a tougher approach, echoing the views of many in civil society. "To leave the seat empty at ASEAN summits is actually their comfort zone," Natalegawa told the Reuters news agency. "They don't have to be held accountable." "Excluding the junta is only part of a series of steps that should be taken," he said, adding that Myanmar presents an "unprecedented challenge" to the bloc's unity. Some in ASEAN, including Thai Foreign Minister and Deputy Prime Minister Don Pramudwinai and Cambodian Prime Minister Hun Sen, have travelled to Naypyidaw to meet Min Aung Hlaing and other senior officials. The NUG says the existing five-point plan lacks an accountability mechanism and is "not enough" to restore peace. NUG Foreign Minister Zin Mar Aung told Al Jazeera that ASEAN should engage publicly with the NUG as "the true representative of Myanmar". ASEAN's charter operates on the principles of consensus and non-interference, adding to the difficulties in crafting a unified response to the crisis. — Agencies