A Japanese newspaper says North Korea has been building concrete foundations at a dozen locations since this summer, creating platforms large enough for intercontinental ballistic missile and other projectile launches.

The Asahi Shimbun carried the revelation in a story published Monday, quoting South Korean and U.S. sources.

According to the report, concrete foundations are built on uneven or unsteady ground in order to prevent damage to mobile launch pads and to ensure a projectile's trajectory is accurate.

It said that South Korea’s National Intelligence Service believes there is a possibility the North will launch a mid- or long-range ballistic missile before year’s end. 

The report added that Seoul and Tokyo are on high alert for fresh North Korean provocations as denuclearization talks between Pyongyang and Washington have failed to make headway.

The report also said that Japanese Aegis destroyers have been deployed in the East Sea since early November as an additional precautionary measure.