Battle of Ongjin The Battle of Ongjin was a part of the Operation Pokpoong that marked the beginning of the Korean War . The ROK 17th Infantry Regiment fought against the DPRK 14th Infantry Regiment and the 3rd Guard Brigade supported by a tank company at Ongjin . Regional characteristics . Ongjin Peninsula is located at the westernmost of the 38th parallel . It is surrounded by the sea , and its only land route was blocked by the 38th parallel . There are strategic mountains at the center of the peninsula that can observe the entire peninsula easily . Prior to the Battle of Ongjin , the two opposing forces already had three clashes near these mountains in 1949 . The DPRK had built supply bases nearby , and supplies could be transported by railroad . On the other hand , ROK forces received support from Port Bupho located at the southeast of the peninsula . Due to the wide range between tidelines , large vessels were only able to come up alongside the Port Bupho pier twice per day . Prelude . From 20 June 1950 , ROK 17th Infantry Regiment began witnessing suspicious and unusual movements on North Korea side of the 38th parallel . The regiment spotted many high - ranking North Korean officers in North Korean bases and on the hills , but no North Korean civilians were seen . When the regiment received an order to call off its alert , regimental commander Paik In - yup ignored the order and kept his regiment on high alert for any possible attacks from North Korea . Eventually , Paik lowered the alert except on the front lines . However , when United Nations personnel visited the regiment they urged Paik to cancel the alert saying that the it would cause the very issue it was in place to prevent . However , the day before the battle Paik ordered every troop to be stationed in their defense positions , giving the regiment a fortunate battle - ready stance for the upcoming attack . Preparation . Democratic People ' s Republic of Korea . Taking over Kangryong as fast as possible was the main goal for North Korean forces . The 3rd Guard Brigade prepared in the west , and the 14th Infantry Regiment with an armored battalion from the 203th Armored Regiment was tasked with capturing Kangryong . Republic of Korea . Ongjin Peninsula is an isolated area where only ground access was to go through North Korean soil . Therefore , 17th Infantry Regiment had to defend a 45 km line with limited troops . The 1st Infantry Battalion covered the west and the 3rd Infantry Battalion covered the east while the 2nd Infantry Battalion was stationed at the rear to act as relief . The regiment focused its strength at the Kangry ' ŏng , protected by the 3rd Infantry Battalion , because it was most likely to be the primary object for North Korea . If Kangry ' ŏng was taken , the regiment would lose its combat strength by half along with its path of retreat . Battle . At 04 : 00 of 25 June a red flare was shot in the air and DPRK forces began shelling ROK defenses for 30 minutes . After the artillery attack , a battalion - sized force of DPRK soldiers thrusted into the ROK 1st Battalion . Two companies of the battalion fought hand - to - hand , but were forced to retreat due to DPRK reinforcement . With the destruction of both wire and wireless communications , 1st Battalion commander Major Kim learned of the situation from retreating forces . He sent a reserve company forward as backup but this effort failed . Major Kim was later killed by DPRK artillery . Meantime , the DPRK 14th Regiment continued shelling on the ROK 3rd Battalion until 05 : 30 . However , ROK forces was not allowed to return artillery fire until hours later because the U . S . advisors had full control over the battalion ' s 105mm artillery . When DPRK forces rushed over the ROK defenses with tanks and armored vehicles , ROK forces employed M18 recoilless rifle in defense . These failed to destroy any tanks . The ROK 3rd Battalion then retreated and set up new defensive lines at Chimasan and Seokgyeri which left Kangryong and Yangwon vulnerable to DPRK attack . Nevertheless , Colonel Paik ordered the 2nd Battalion to aid the 1st Battalion to maintain defense line on the left . The 2nd Battalion ambushed and annihilated a DPRK battalion then recovered the left of the line in a counterattack . The battalion then retreat orders but refused and maintained the defensive line until the battalion learned the regiment had withdrawn to Kangryong . The battalion commander Major Song led both the 1st and 2nd Battalions to Buldangsan . When the troops arrived at Buldangsan , the DPRK forces had already taken over Yangwon and Kangryong . Major Song abandon plans to move to Port Bupho . Instead , he moved his forces to Sagot and retreated from there . After retreating from Kangryong , the 3rd Battalion made its final defensive line and engineers blasted bridges to halt DPRK tanks . However , the DPRK forces did not chase down the ROK troops . Later it was learned that the DPRK 14th Regiment transferred the operation to the DPRK 3rd Guard Brigade after taking over Kangryong and moved to a different area to join larger battles . LST - 801 came to Port Bupho at 23 : 30 and most of the 3rd Battalion boarded . Heavy equipment and supplies except one M101 howitzer were either burnt or thrown into the sea . Colonel Paik ordered LST - 801 to set sail . He remained with the 7th Artillery Battalion , where he worked with its commander , Major Park , and other officers till the last round was fired . They successfully fled the zone in a small wooden boat . Aftermath . About 90 % of the South Korean forces and equipment in Ongjin Peninsula returned to the mainland . The 17th Infantry Regiment moved to Daejeon and recovered all losses . The regiment returned to the front line at Osan and participated in later battles including the Battle of Inchon .