Taiwan's defense ministry is reporting the presence of multiple Chinese spy flights in airspace above the island.

A single spy flight was detected crossing over the island on Monday, followed by three more on Tuesday — just days before a pivotal presidential election that will have ramifications on China-Taiwan relations.

Defense Ministry spokesman Maj. Gen. Sun Li-fang told the press Tuesday that the spy flight appears to be built to collect atmospheric data, but whether it has other functions is unknown.

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Taipei skyline

A view of Taipei 101 outside the Presidential Office Building, Taipei, Taiwan. (Tommy Walker/NurPhoto via Getty Images)

Sun said the government "is closely monitoring and controlling the situation, taking appropriate measures, and summarizing their flight paths for judgment and analysis," according to The Wall Street Journal.

Last year, the U.S. documented a similar spy flight that flew across America before being shot down on the coast of South Carolina.

Another Chinese spy flight was discovered after it crashed into the Pacific Ocean near Hawaii. Another three Chinese surveillance crafts were found to have flown over Texas, Florida and Guam during the Trump administration.

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The suspected Chinese spy balloon drifts to the ocean after being shot down

A suspected Chinese spy flight drifts to the ocean after being shot down last year off the coast of Surfside Beach, South Carolina. (Randall Hill/Reuters)

It is unclear how long Beijing has been operating the espionage program that relies on dated spy flight technology along with modern surveillance techniques. Spy flights have been spotted over five continents since 2018. 

The program has been largely run out of China’s Hainan Island province off its southeast coastline in the South China Sea by the People’s Liberation Army (PLA). It has been known to operate over regional neighbors like Japan, Taiwan, Vietnam, the Philippines and India.

But these spy flights, used to collect military intelligence from nations that are of strategic interest to Beijing, have also emerged over the U.S. before.

Taiwan election

Lai Ching-te (L), presidential candidate from the ruling Democratic Progressive Party (DPP), shakes hands with Ko Wen-je (R), presidential candidate from the opposition Taiwan People's Party (TPP), as Hou Yu-ih (C), presidential candidate from the main opposition Kuomintang (KMT), looks on during a debate in Taipei. ((Photo by Huang Shih-chi / POOL / AFP) (Photo by HUANG SHIH-CHI/POOL/AFP via Getty Images))

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According to opinion polls, the current frontrunner to become Taiwan's next president is the ruling Democratic Progressive Party's nominee, Lai Ching-te.

Taiwan's main opposition party, the Kuomintang, traditionally supports close ties with the mainland and has vowed to reopen talks with China if it wins the election. But the Kuomintang also says Taiwan's people will decide their future. 

Fox News Digital's Jennifer Griffin, Houston Keene, and Caitlin McFall contributed to this report.