At a news conference in Beijing, ministry spokesperson Zhao Lijian said China had deposited its instrument of accession and completed “all legal procedures to join this treaty,” daily Global Times reported.
“The treaty will become effective for China after 90 days,” he said.
Zhang Jun, China's permanent representative to the UN, submitted the document to UN chief Antonio Guterres.
In a statement, the Chinese diplomat said Beijing “attaches high importance to the problems caused by illicit transfer and abuse of conventional arms.”
“China supports the purposes and goals of the treaty and agrees on taking necessary measures to regulate international arms trade and combat illicit arms transfer,” he said in the statement quoted by the state-run Xinhua News Agency.
China has become the 107th country to join the treaty, which was approved by the UN in April 2013 and came into force in December 2014.
The pact aims to “establish the highest possible common international standards for regulating … the international trade in conventional arms … [and] prevent and eradicate the illicit trade in conventional arms.”
The US is not a party to the treaty, having backtracked after initially signing the pact in 2013.
Ambassador Zhang highlighted Washington’s status in his statement, without explicitly naming the US
“[A] Certain country has quit multilateral arms control agreements and international treaties and organizations in succession, walked away from international commitments, and launched acts of unilateralism and bullying,” he said.
“This has brought huge uncertainties to the global strategic balance and stability, and seriously undermined the joint efforts of all countries to tackle global challenges.”
He urged all major powers to “set an example by contributing to safeguarding the international order, the rule of law, the role of the UN and multilateralism.”