Japan’s government said on Tuesday that North Korea may be preparing for another missile launch.

Japanese Chief Cabinet Secretary Yoshihide Suga reportedly told a press conference in Tokyo that the government is analyzing signals that may indicate that Pyongyang is getting ready to fire another projectile.

North Korea’s last test was the launch of a Hwasong-12 intermediate-range ballistic missile near Japan on September 15.

“North Korea’s missile launches are a high priority, and we are analyzing the situation carefully,” Kyodo News quoted Suga as saying. “We will do all we can to monitor and observe the situation.”

Pentagon spokesman Robert Manning reportedly said that Washington is continuing to monitor the latest developments.

The Kyodo story speculated that Japanese technicians might have detected an ordinary radio signal from North Korean military training exercises that are unrelated to potential missile launch.

But reports from other sources earlier this week suggested that the North is preparing for another missile launch or nuclear test explosion.

The Center for Strategic and International Studies (CSIS), a respected US think tank, said on Sunday that there’s an increasing possibility that North Korea will engage in significant “weapons of mass destruction activities” in the next 30 days. CSIS said such activity might include a new ballistic missile test around December 17.

Radio Free Asia, a US government-backed news outlet, also quoted a Chinese source over the weekend as saying that Pyongyang will probably carry out one more big nuclear test.