North Korea increasing her western coast line according to a CIA report dated June 1968

An item reported that North Korea relocated some of her motor gun boats by transferring the boats from the East Sea to the West Sea Fleet. By doing this was the coastal defence furthermore increased especially near the seaward approaches to the harbour of Inchon, South Korea. The motor gunboats indicated as so-called P-6PGM units were converted P-6 torpedo boats of which the torpedo tubes were removed and instead armed with 2-3,7cm main mounts and 2-2barrel 2,5cm secondary mounts. Six of such boats were stationed at the Haeju and the Saigon-ni naval bases along the west coast. The conversion was probably executed at the Yondangpo Shipyard near Haeju. At the Kosong Naval Base of the East Sea Fleet were 3 P-6 torpedo boats stationed and a fourth one at the West Sea Fleer Nampo Naval Base. Furthermore were at sea six well armed large gunboats (SO-1 PGM, Chodo PGM and K-48PGM types) generally active around Inchon. There were several explanations for this strong force, one preparing measures against ROK (1) attacks on the North Korean coastline, an offensive force to harass the merchant shipping around Inchon or protection of the North Korean fishery fleet against the ROK-forces

Note
1. ROK forces are the armed forces of South Korea. Since 8 September 1945 is Korea divided in two countries North and South Korea, first controlled by the USA and the Soviet Union. On 15 August 1947 was the Republic of South Korea and on 9 September 1948 the Democratic People’s Republic of Korea founded.

Source
The report was published on www.archive.org, document number CIA-RDP78T04759A008400010124-8