TAIPEI/BEIJING (REUTERS) - China said on Wednesday (Nov 30) it "highly appreciates" Malaysia's adherence to the one-China policy in its handling of telecom fraud cases.

The remarks came after Taiwan expressed its "stern opposition" to Malaysia's deportation of 21 Taiwanese suspected of multi-million dollar telecom fraud to China.

The Taiwanese were among 74 fraud suspects who were escorted from Malaysia by Chinese police and arrived in Wuhan in central China late on Tuesday (Nov 29). The other 53 were all Chinese, Xinhua news agency said.

"China highly appreciates Malaysia's firm adherence to the one-China policy when handling the cases and its cooperation with China on fighting cross-border crimes," said Foreign Ministry spokesperson Geng Shuang at a daily press briefing on Wednesday.

Such an act helps to thoroughly investigate the cases, recover illicit money, punish crimes in line with the law and safeguard victims' legal rights, Geng said.

The suspects were allegedly involved in over 500 cross-border telecom and cyber fraud cases involving over 60 million yuan (S$12.5 million), according to Xinhua.

Taiwan's Foreign Ministry expressed regret over Malaysia's handling of the case in a statement on its website.

"This action by Malaysia has seriously harmed the rights of our citizens, and harms the long standing friendship between Taiwan and Malaysia," it said.

The statement also said Taiwanese police had been working with Malaysia to arrange for the suspects to be returned to Taiwan but Beijing had pressured the Malaysian government to send all suspects to the mainland.

Taiwan's Mainland Affairs Council, its China policymaker, said Beijing's unilateral action "damages the tacit understanding and foundation for cooperation between security agencies".

It said in a statement that cracking down on cross-border telecom fraud depended on cooperation from both sides.

Malaysia's foreign ministry did not immediately comment on the deportations.

Malaysia does not have diplomatic relations with Taiwan and treats the island as part of China in line with Beijing's "one China" principle, which considers Taiwan a breakaway province.

China has suspended its main dialogue mechanism with Taiwan since the election of Ms Tsai Ing-wen as Taiwan's president earlier this year, somebody China views as promoting the island's formal independence.