Fresh cross-border clashes between Thailand and Cambodia broke out on Sunday hours after US President Donald Trump announced the two Southeast Asian nations had agreed to ceasefire talks.

Following up on calls by President Trump, Secretary of State Marco Rubio spoke with his counterparts in both countries. But on Sunday morning, skirmishes erupted once more.

Thailand expressed cautious support. Phumtham thanked Trump and said that Thailand agreed in principle to a ceasefire but stressed the need for “sincere intention” from Cambodia, the Thai Foreign Ministry said. Phumtam called for swift bilateral talks to discuss concrete steps toward a peaceful resolution, it said.