SEOUL, July 25 (Xinhua) -- The Democratic People's Republic of Korea (DPRK) fired two unidentified projectiles into the eastern waters early on Thursday, according to South Korea's Joint Chiefs of Staff (JCS).

The projectiles were launched near the DPRK's eastern coastal city of Wonsan at 5:34 a.m. and 5:57 a.m. local time respectively, the JCS said in a statement.

The JCS said later that the first projectile of the two flew about 430 km, while the second one traveled around 690 km, based on the joint analysis by South Korea and the United States, according to local media reports.

The projectiles, believed to be new types of short-range missiles, landed in the East Sea after traveling at an altitude of some 50 km. They were reportedly estimated to have been fired from mobile launchers.

The military authorities of South Korea and the United States were analyzing what the projectiles were, the JCS said.

The South Korean military maintained a defense posture, closely monitoring relevant situations in preparation for a possibly additional launch.

It was the DPRK's first launch of projectiles since the country fired projectiles twice in May. During the latest launch of two projectiles on May 9, those flew about 420 km and 270 km each.

South Korea's National Intelligence Service (NIS) saw the DPRK's projectile launches as a protest against the planned South Korea-U.S. joint military exercise, called "Dong Maeng 19-2," scheduled for next month.

The DPRK's foreign ministry warned last week that Pyongyang might end the scheduled working-level negotiations with Washington if the planned South Korea-U.S. military drills happen.

The presidential Blue House of South Korea said in a statement that it was closely managing situations relevant to the DPRK's "short-range missile" launches through the National Security Office (NSO) crisis management center.

South Korean President Moon Jae-in was briefed on it immediately after the launches, the Blue House said.

The South Korean government had closely monitored situations as it recognized the relevant situations "in advance," and it was running a rapid response system among relevant ministries.

According to local media reports, the military authorities of South Korea and the United States spotted signs of the preparation for the DPRK's projectile firings two weeks ago.

The Blue House said the intelligence authorities of South Korea and the United States were precisely analyzing the DPRK's short-range missiles.

The NSO meeting will be held later in the day to discuss the DPRK's missile firings, the Blue House added.

Lee Do-hoon, South Korea's special representative for Korean Peninsula peace and security affairs, held phone talks with Stephen Biegun, U.S. special representative for DPRK affairs, and Kenji Kanasugi, director general of Asian and Oceanian affairs bureau at Japan's foreign ministry, according to Seoul's foreign ministry.

The telephone communication was held to share and analyze intelligence on the DPRK's projectile launches.

The Seoul ministry said it will closely communicate with the United States and Japan, while planning to consult with China and Russia on the issue.