HONG KONG (AP) — Foreign ministers from Cambodia and Thailand convened with their Chinese counterpart on Monday as the Beijing government, building on its expanding presence in the world diplomatic arena, sought to play a stronger mediating role in the violent border dispute between the two Southeast Asian countries. The trilateral meeting, held in a southwestern Chinese province north of the contested border, came two days after Thailand and Cambodia signed a fresh ceasefire agreement to end weeks of fighting that killed more than 100 people and forced the evacuation of hundreds of thousands on both sides of the border.