The bus, carrying around 40 passengers, was travelling from the centrally-placed Bago province when it plunged off a highway near Myawaddy, a town on the Thai border.
The negotiation started as early as 2001 when the Philippine government initiated the peace talks and invited the Malaysian government to serve as a third party facilitator.
The test came as US Secretary of State Rex Tillerson warned the UN Security Council that failure to curb North Korea's missile threat could lead to "catastrophic consequences".