KUALA LUMPUR - A U.S. Air Force plane that may include House of Representatives Speaker Nancy Pelosi among its passengers entered the final leg of its journey to Taiwan after departing from Malaysia and taking an extended route that skirted the South China Sea.

Reuters could not immediately establish if Pelosi or her delegation were on flight SPAR19. Pelosi did not confirm if she was visiting the self-governed island, which Beijing claims as its own, but sources earlier told Reuters she was expected to arrive in Taiwan's capital Taipei later on Tuesday.

The plane left Malaysia's capital Kuala Lumpur at 3:42 p.m. (0742 GMT) on Tuesday and flew east toward Borneo on a route that skirted the South China Sea.

It was last seen north of the Philippines, according to Flightradar24, in the tracking site's most followed flight on Tuesday.

Since last week, China's People's Liberation Army has conducted various exercises, including live-fire drills, in the South China Sea, Yellow Sea and Bohai Sea, in a show of Chinese military might.

A visit to Taiwan by Pelosi, who is second in the line of succession to the U.S. presidency and a long-time critic of China, would come amid worsening ties between Washington and Beijing.

As of 1354 GMT, SPAR19 was about 500 km (310 miles) southeast of Taipei in a journey that has so far lasted more than five hours, according to Flightradar24, on a flight tracked by as many as 300,000 people on its website earlier in the day.

A normal flight from Kuala Lumpur to Taiwan's capital of Taipei would cross the South China Sea, with a typical flight time of under five hours.

(Reporting by Ebrahim Harris and Rozanna Latiff in Kuala Lumpur and Ryan Woo in Beijing; Additional reporting by Neil Jerome Morales in Manila; Editing by Martin Petty, William Maclean, Will Dunham and Frank Jack Daniel)