The website of Taiwan's presidential office received an overseas cyberattack on Tuesday and was at one point malfunctioning. The website was shortly brought back online, the source told Reuters.
This happened ahead of US House of Representatives Speaker Nancy Pelosi's expected visit to Taipei.
US House Speaker Nancy Pelosi arrived in Taiwan on Tuesday night, becoming the highest-ranking American official to visit the self-ruled island that is claimed by China in 25 years.
Pelosi's visit has triggered increased tensions between China and the United States. China claims Taiwan as part of its territory, to be annexed by force if necessary, and views visits by foreign government officials as recognition of the island's sovereignty.
China had warned of "resolute and strong measures" if Pelosi went ahead with the trip. The Biden administration did not explicitly urge her to call it off, while seeking to assure Beijing it would not signal any change in U.S. policy on Taiwan.
Plane carrying Nancy Pelosi becomes world's most tracked flight
The US Air Force's Boeing C-40C - SPAR19 which is carrying US House Speaker Nancy Pelosi to Taiwan is currently the world's most tracked aircraft.
According to flight-tracking website FlightRadar24, around 320,000 users are following every move of Pelosi's flight.
Internet users are speculating whether the Democrat Congresswoman will go ahead with a highly controversial visit to Taiwan against the wishes of the Biden administration.
(With inputs from agencies)