Prime Minister Samdech Akka Moha Sena Padei Techo Hun Sen (Pic. 1) and South Korean Ambassador to Cambodia H.E. Park Heung-kyeong (Pic. 2) this morning cut red ribbon to officially put into use the 63.6-kilometre-long National Road No. 21 from Takhmao Roundabout in Takhmao town to Chrey Thom in Koh Thom district, Kandal province, built under a concessional loan from the Government of the Republic of Korea.