The leaders of Cambodia and Thailand have agreed to meet to negotiate a ceasefire, according to a social media post by United States President Donald Trump on Saturday.

Cambodian Prime Minister Hun Manet stated the dialogue was co-organised by the United States, with China’s participation.

The Thai warning came as the U.S. expressed its grave concern about the most serious fighting in years between the Southeast Asian neighbors. The U.S. and China compete for influence in fast-growing Southeast Asia, and both have good relations with Thailand and Cambodia.

As the Cambodia-Thailand border conflict enters its fourth day, monks, dancers, and civilians offer shelter, food, and aid to those over 168,000 people displaced.