SEOUL-- An airplane of the same jet type used by North Korean leader Kim Jong-un was spotted to have flown to the east coast, according to an aviation tracker, briefly raising speculation that Kim might have headed to his vacation home.

But the AN-148 jet, which took off from Pyongyang at 9:08 a.m. Thursday, was found later to have a different registration number, P-672, from the jet used as Kim's personal plane, with a registration number of P-671, according to Flightradar24, a flight tracking website.

The jet headed in the direction of the east coast town of Wonsan, but its last signal was recorded near the east coast, according to Flightradar24. Sources said the plane appears to have returned to Pyongyang without landing in Wonsan.

The North Korean leader has reportedly been staying in Pyongyang.

The flight comes amid lingering tensions on the Korean Peninsula after North Korea warned the South of a "serious security crisis" in apparent protest against the joint military exercises between Seoul and Washington.

Source: Yonhap News Agency