SEOUL, Aug. 21 (Xinhua) -- South Korean President Moon Jae-in on Monday urged the Democratic People's Republic of Korea (DPRK) not to conduct any provocation as the joint war game with the United States kicked off.

Moon told a cabinet meeting that the Ulchi Freedom Guardian (UFG) is an annually-held joint military exercise that is defensive in nature, saying South Korea has no intention to escalate military tension on the Korean Peninsula.

The UFG computer-assisted simulation exercise began earlier in the day, mobilizing about 17,500 U.S. soldiers and some 50,000 South Korean troops. The U.S.-South Korea joint war game would last till the end of this month.

Moon said the DPRK should neither distort South Korea's efforts to maintain peace nor conduct provocative acts, which worsen situations, under the pretext of this exercise.

The DPRK tested what it called an intercontinental ballistic missile (ICBM) twice in July. It was followed by the war of words between Pyongyang and Washington, which escalated tension on the peninsula.

It was not known whether the U.S. forces would mobilize strategic assets, such as nuclear-powered aircraft carrier and nuclear-capable bombers, to the UFG war game.

The DPRK, Moon said, did not stop its efforts to advance the nuclear and missile technologies, while the international community strengthened pressure and sanctions on Pyongyang.

The peninsula's security situations got graver than ever because of the recent developments, the president said.