TAIPEI (Taiwan News) — The Ministry of National Defense (MND) announced that a Chinese balloon was detected crossing the Taiwan Strait median line on Monday (Dec. 18).

The MND said one "PRC balloon" was detected at 09:09 a.m. on Monday, around 124 km (67 nautical miles) northwest of Keelung at an altitude of approximately 4,572 m (15,000 ft). The balloon then headed east and "disappeared" at 11:52 a.m., according to the MND.

In addition, the defense ministry also announced that four People's Liberation Army (PLA) aircraft and three naval vessels were tracked around Taiwan from 6 a.m. Monday to 6 a.m. Tuesday (Dec. 19). None of the aircraft crossed the median line or entered the southwest corner of the air defense identification zone (ADIZ).

When asked by Taiwan News whether the balloon was used for surveillance, an MND spokesperson said the preliminary assessment is that it was a weather balloon.