Photos captured by U.S. satellites have reportedly detected preparations for a North Korean long-range missile launch.

Quoting two defense officials, AFP reported on Friday that the latest movements are similar to those detected shortly before the North launched a long-range missile last month.

The Associated Press also quoted U.S. officials as saying that there are indications of increased activity at a site used to fire long-range missiles in the North.

U.S. broadcaster Fox News quoted a senior U.S. intelligence official as saying that Washington detected some “troubling” activities of vehicles and staff at the North’s research and development complex at Saneum-dong, and that the moves were similar to those observed prior to the North’s launch of a Daepodong Two missile last month.