By Lee Min-hyung

The U.S. and South Korean governments have shattered concerns over a recent report on "undeclared" missile bases in North Korea, saying the allies have already recognized the existence of the facilities and continue to keep a close watch on them.

"We fully know about the sites being discussed, nothing new ― and nothing happening out of the normal," U.S. President Donald Trump said on Twitter, Tuesday.

"(They are) just more fake news. I will be the first to let you know if things go bad," he said.

The message was aimed at countering the report released by the Washington-based Center for Strategic and International Security (CSIS) which claimed it had identified locations for 13 out of 20 secret missile bases in the North.

The report has particularly highlighted one of the bases in the North's Sakkanmol, about 137 kilometers northwest of Seoul, as a potential threat to South Korea, as it is the closest to the border region and remains "reasonably well-maintained."

With the report making headlines here and abroad, South Korea also expressed a sense of embarrassment. Cheong Wa Dae said it has already paid close attention to the reported missile bases and no provocative gestures have been detected there.