Taiwan has reported spotting several Chinese balloons flying over the island and near a key air force base in the past two days, amid heightened tension in the Taiwan Strait ahead of the island’s presidential election next month.

According to Taiwan’s Defense Ministry, four balloons were detected on Tuesday (1/2/24) and today (1/3/24), three of which passed near the Hsinchu Air Base, where some of Taiwan’s most advanced fighter jets are stationed. The ministry said the balloons were flying at an altitude of about 8,000 meters (26,000 feet) and were likely used for meteorological observation or high-altitude scientific research.

However, some experts have raised concerns that the balloons could also carry intelligence-gathering equipment or serve as decoys for Chinese military aircraft and ships that frequently enter Taiwan’s air defense identification zone (ADIZ) or cross the median line of the strait.

Jeremy Hung, a researcher at the Taiwanese think tank the Institute for National Defense and Security Research, told Newsweek that the balloons’ relatively low altitude indicates they are unlikely to be spy balloons, but added that “this does not mean that these balloons are unrelated to collecting information about Taiwan.”

Ben Lewis, a U.S.-based defense analyst, told TaiwanPlus that the balloon activity could be a way for China to test Taiwan’s response capabilities and readiness, or to distract Taiwan’s attention from other potential threats.

China claims Taiwan as its own territory and has never renounced the use of force to bring it under its control. Beijing has ramped up its military pressure on Taiwan since 2020 when high-ranking U.S. officials visited Taipei and expressed support for the island’s democracy and security.

Taiwan’s President Tsai Ing-wen, who is seeking re-election on January 20th, has vowed to defend Taiwan’s sovereignty and resist China’s coercion. She has also called for dialogue and stability in the cross-strait relations.

China’s Foreign Ministry did not respond to requests for comment on the balloon incidents. China opposes any official contact or military ties between Taiwan and the U.S., and has in the past urged Washington to abide by the one-China principle and the three joint communiques.

Taiwan’s Defense Ministry said it monitored the situation with combat aircraft, navy vessels, and land-based missile systems, and warned China not to provoke or escalate tensions in the region.