Thailand and Cambodia agreed Monday to an unconditional ceasefire during a meeting in Malaysia, in a significant breakthrough to resolve five days of deadly border clashes that have killed dozens and displaced tens of thousands.

Thailand and Cambodia are disputing whether their ceasefire is holding, the morning after they agreed to stop fighting in a deal reached in Malaysia under U.S. pressure.

Malaysian Prime Minister Anwar Ibrahim says Thailand and Cambodia have agreed to an “immediate and unconditional” ceasefire in an effort to resolve deadly border clashes.