The US Navy amphibious assault ships USS Bonhomme Richard, bottom, and USS Boxer, second from top, are underway with the Republic of Korea Navy Dokdo Amphibious Ready Group in the East Sea during exercise Ssang Yong 2016, March 8, 2016. [Photo/Agencies]

SEOUL -- The Democratic People's Republic of Korea (DPRK) fired two short-range ballistic missiles into its eastern waters in an apparent show of force against joint annual war games between Seoul and Washington and new harsher sanctions against Pyongyang, Yonhap news agency reported Thursday.

Yonhap quoted the the Republic of Korea's Joint Chiefs of Staff (JCS) as saying that two short-range ballistic missiles, believed to have been Scud missiles, were launched at 5:20 a.m. (2020 GMT Wednesday) from the North Hwanghae province in the DPRK's western region. The missiles flew about 500 km and landed in waters northeast of the DPRK's coastal town of Wonsan in the East Sea.

It marked the first time in 2016 that DPRK forces fired short-range ballistic missiles. Pyongyang fired off six rounds of its 300-mm multiple rocket launchers into eastern waters on March 3.

The firings of short-range missiles and artillery shells in the past week were seen as an apparent show of anger at the joint US-ROK military exercises that kicked off on Monday in the largest-ever scale.

The drills, codenamed Key Resolve and Foal Eagle, will run through April 30, mobilizing a nuclear-powered US aircraft carrier and its attendant fleet, a nuclear-capable submarine and aerial tankers to refuel fighter jets.

The US show of military strength during the drills would come after the DPRK's latest nuclear test and long-range rocket launch.

DPRK started off a new year with the testing of what it claimed was its first hydrogen bomb on Jan. 6 and followed up with the launch of a long-range rocket, which outsiders see as a disguised test of missile technology, on Feb. 7.

The UN Security Council unanimously approved new tougher sanctions on Pyongyang on March 2, including a ban on all cargo heading to and from the DPRK and its exports of coal and mineral resources.

The ROK?imposed standalone sanctions on the DPRK, including a ban on third-country ships having docked at the DPRK within 180 days from accessing ROK ports.