The "large-scale" exercises were being conducted in the seas and skies off China's east coast in the Yellow Sea and Bohai Gulf, and included the firing of dozens of missiles, a notice posted late Monday on the Ministry of Defence website said.
Naval and air force assets including dozens of ships, more than 10 aircraft, submarines and an unspecified number of coastal defence personnel took part in the drills, which the ministry said were aimed at testing weapons and honing the military's abilities in conducting coastal assaults and intercepting air targets.
The ministry did not specify how long the drills were to last but a four-day shipping ban ending on Tuesday was issued for the area where the drills were held, according to notices by the military and local authorities.
It was not immediately clear whether the wargames were meant to send any sort of message.
But the announcement comes just days after China backed a US-drafted UN Security Council resolution passed on Saturday that significantly stiffened sanctions against North Korea for its pursuit of nuclear and missile weapons systems.
In the wake of the resolution's passing, China has reiterated its resolve to side with the international community in opposing North Korea's nuclear weaponisation and aggressive sabre-rattling.
China has for some time been engaged in a modernisation of its once-backward armed forces, seeking military clout commensurate with its economic might, a drive that has caused unease among its regional neighbours.
China also has consistently railed against recurring US-South Korean wargames that are directed at deterring a North Korean attack, but which China blames for fanning regional tensions.
North Korea vowed Monday that the tough new UN sanctions would not stop it from developing its nuclear arsenal, rejecting talks and angrily threatening retaliation against the United States.