China has always opposed to the proliferation of weapons of mass destruction and has urged the international community to conclude a treaty banning space-based weapons, Qin said.

秦刚说，中国一贯反对大规模杀伤性武器的扩散，并敦促国际社会签订禁止开发太空武器的条约。

Conclude a treaty with the country

与该国缔结条约

Conclude an agreement (a treaty) with. . .

与…签订协定（缔结条约）。