
Hun Sen said his country's border dispute with Thailand is "worsening."
The Cambodian leader has described the three-day stand-off at the disputed Preah Vihear temple as "very bad" for relations.
His comments are contained in a letter to Thai Prime Minister Samak Sundaravej.
Earlier, the Cambodian military said Thai troops had again crossed the border, saying some 400 soldiers are now in the country.
Thailand has denied the allegation, insisting it has troops in the border area, but none in Cambodia itself.