Cathay Pacific
Cathay Pacific Airways passenger planes taxi along the tarmac at the Hong Kong Airport Sept. 11, 2013. Reuters/Tyrone Siu

Taiwanese officials have warned Hong Kong about a possible bomb aboard a Cathay Pacific or Dragonair flight arriving from China in the next two days, after receiving intelligence from the National Security Bureau, authorities at Hong Kong Airport and two other airlines said Friday.

The suspect is believed to be a woman who might board a flight operated by either of the two carriers to Hong Kong on Friday or Saturday, the South China Morning Post, or SCMP, said, citing a source among airport police in Taiwan. The warning comes amid a major crackdown by China on domestic terrorists following a series of attacks mostly in the restive region of Xinjiang, which is home to the minority Muslim Uighur group. Nine people were sentenced to death on Thursday after authorities announced the arrest of 29 people described as "violent terrorist criminal suspects."

"We are aware of a threat message with reference to our flights from mainland China to Hong Kong as shared by the Taiwan authorities," a spokesperson for Cathay Pacific, and its unit Dragonair, said in an emailed statement to Reuters. "We will continue to work closely with the relevant authorities and have reminded our frontline teams to remain vigilant as usual."

The warning also comes two days after tens of thousands of people participated in a vigil in Hong Kong to mark the 25th anniversary of the bloody crackdown on pro-democracy protesters in Beijing's Tiananmen Square in 1989.

The bomb warning was confirmed by spokespersons from the Hong Kong Airport Authority, Taiwan's Civil Aeronautics Administration and Hong Kong-based low-cost airline HK Express, according to Reuters, while Hong Kong Airport authorities said flight operations at the airport remained normal on Friday.

Jeff Sun Jianfeng, vice-president of Hong Kong Airlines, reportedly confirmed the threat stating that an alert had already been sent to all ground staff, pilots and cabin crew.

"Information received that a Security THREAT might occur on flights to/from China and Hong Kong on the coming 2 days,” a document from the intelligence read, according to SCMP. "[All] flights to/from China and Hong Kong on 06-07Jun2014 are required to apply for Enhanced Flight Deck Entry/Exit Procedure and crews are required to raise their awareness of in-flight security."

While authorities confirmed the threat warning, Jianfeng said, according to SCMP, that it was only a “low-level” alert. A spokesperson for the Hong Kong police also reportedly said that there had been no concrete intelligence to indicate that the city was a target of terrorism.