Truman agreed, and on June 30 he told MacArthur to use all forces available to him. MacArthur, however, recommended committing a U.S. Truman then extended American air and naval actions to North Korea and authorized the use of U.S.

The next day, as the situation worsened, the United Nations requested its members to furnish military assistance to repel the invasion. The following day, Truman sanctioned the use of American air and naval forces below the 38th parallel. Truman directed General of the Army Douglas MacArthur, whose Far East Command (FEC) was located in Tokyo, to evacuate American dependents from Korea and send ammunition to the beleaguered ROKA. Security Council denounced North Korea's actions and called for a cessation of hostilities and withdrawal of the NKPA to the 38th parallel. The ROKA fled south in disarray across the Han River toward Pusan, a major port at the southeastern tip of the Korean peninsula. Spearheaded by tanks, NKPA forces moved rapidly through the Uijongbu Gap on the west side of the Korean peninsula and captured Seoul, South Korea's capital. Korean Military Advisory Group, the ROKA was overwhelmed. The 98,000-strong ROK Army (ROKA), its combat training incomplete, and having no tanks and only 89 howitzers, was no match for the better-equipped NKPA. Many of the NKPA were battle-tested, having served in the Chinese and Soviet armies in World War II. Tank crews had to watch as carefully as infantry for land mines.The Korean War began with a surprise attack June 25, 1950, when eight divisions and an armored brigade (90,000 soldiers) of the North Korean People's Army (NKPA) attacked in three columns across the 38th parallel and invaded the Republic of Korea (ROK). It was in this role that American Sherman crews came into contact with Australian troops, as they did in the battle of Kapyong, April 1951. After several large tank battles in July and August 1950, the American armoured units' most common task was the support of infantry operations.

Armed with a 76 mm gun, the Sherman was outclassed by North Korea's T-34/85 tanks. It was powered by a Ford eight-cylinder petrol engine and could attain a top speed (on road) of 48 kilometres per hour. The M4A3E8 version of the Sherman had a crew of five. The most widely used Allied tank in the Second World War, the Sherman tank, again saw service with American armoured units in Korea.

Tank battles in korean war