Thailand launched airstrikes along the disputed border with Cambodia on Monday as both sides accused the other of breaking a ceasefire that halted fighting earlier this year.

Longstanding border disputes erupted into five days of combat in July that killed dozens of soldiers and civilians. U.S. President Donald Trump pushed the Southeast Asian neighbors to sign a truce agreement in October, but tensions have continued to simmer.

The Thai army said that more than 50,000 people have left areas near the border for shelters, while Cambodia`s Information Minister Neth Pheaktra said that tens of thousands of residents had been displaced from several villages near the border.

The latest round of clashes has killed at least one Thai soldier and four Cambodian civilians, officials said.

Thai Prime Minister Anutin Charnvirakul said in a televised speech that military operations would be carried out as necessary to defend the country and protect public safety.

"Thailand has never wished for violence. I`d like to reiterate that Thailand has never initiated a fight or an invasion, but will never tolerate a violation of its sovereignty," he said.