Taiwan accused China Monday of kidnapping eight Taiwanese who had been cleared of criminal charges by a court in Kenya, and angrily demanded their immediate return from the mainland.

The alleged abduction -- described by Taiwan's foreign ministry as "illegal" and "uncivilised" -- posed a potential challenge to president-elect Tsai Ing-wen, who takes office next month.

Kenyan authorities in November 2014 arrested 28 Taiwanese along with 49 other ethnic Chinese on charges of illegally entering the African state and being involved in an telecoms scam, the foreign ministry said in a statement.

A first group of 37 suspects, among them 23 Taiwan citizens, was found not guilty by a Kenyan court on Tuesday last week.

But eight of the 23 Taiwanese, were deported to China by Kenyan authorities last Friday due to Chinese pressure, it said.

Taiwan has no diplomatic ties with Kenya, which recognises the government in Beijing. Its nearest diplomat is based in the South African capital.

The ministry said China used "technical methods" to delay news of the Kenyan court's verdict.

"By the time our official rushed to the airport, the eight Taiwan citizens had been forcefully taken to a passenger plane of China Southern Airlines and sent to the mainland," it said.

"Officials from the Chinese mainland abducted the eight Taiwan nationals who had been cleared of the charges by a Kenyan court and sent them to the mainland," it said.

"The illegal and uncivilised measures have severely infringed upon the fundamental human rights of the eight people."

The ministry demanded that the mainland immediately return the eight to Taiwan, and called on Kenyan authorities to free the other 15 acquitted Taiwanese.

Asked to comment on the row, China's foreign ministry spokesman Lu Kang said: "We need to check on the details, but we need to note that the One China policy should be upheld."

China still regards Taiwan as part of its territory awaiting reunification, by force if necessary, even though Taiwan has ruled itself since 1949.

In reply to queries raised in parliament, Shih Hui-fen, deputy minister of Taiwan's Mainland Affairs Council, said a protest was filed to mainland authorities at Friday midnight.

"This has not only harmed the fundamental human rights (of the group), but has hurt Taiwan people's feelings and has severe negative impact on ties between the two sides," Shih said.

The incident also angered the China-sceptic Democratic Progressive Party (DPP), which secured a landslide victory over the China-friendly Kuomintang (KMT) party in January.

The DPP's Tsai Ing-wen will be inaugurated as president on May 20 to replace the KMT incumbent Ma Jing-Yeou.

KMT parliamentarian Ma Wen-chun demanded a more dramatic protest by the government.

"More things like this could happen in the future as cross-strait ties face uncertainties," she said, referring to the change of presidency.

In 2011 Chinese authorities returned 14 Taiwanese suspected in a major fraud case after the Philippines had deported them to China.

That came after nearly four months of efforts to secure their return.

Taiwan and the mainland in 2009 signed a joint crime-fighting and judicial assistance agreement amid improving ties.

However, many Taiwanese have turned their backs on China as they fear closer ties may erode the island's freedoms.

cty/sm

China Southern Airlines