Taiwan said Friday China had blocked it from attending a major United Nations aviation meeting, the latest setback to its troubled campaign for international recognition.

Beijing hit back at the criticism, saying the island had "no right" to be invited.

Self-ruling Taiwan is routinely prevented from attending global forums by Beijing, which still sees it as part of its territory requiring reunification.

But the island had been hoping to attend the triennial meeting of the UN aviation agency in Montreal later this month, after it was admitted in 2013 in a major breakthrough.

That invite came under previous Beijing-friendly president Ma Ying-jeou.

But ties with China have rapidly turned frosty under new leader Tsai Ing-wen, who took office in May.

Taiwan's Mainland Affairs Council (MAC), which handles relations with Beijing, said Friday the island had not been admitted to the International Civil Aviation Organization (ICAO) meeting "due to political interference from China".

"(It) is a great loss for international aviation safety and the public's right to welfare protection," the MAC said in a statement.

Beijing said the move reflected the fact that Taiwan was not a sovereign state.

"The ICAO is a special agency of the UN, and only sovereign countries can take part in it," Chinese foreign ministry spokesman Lu Kang said at a regular briefing Friday.

"Taiwan is part of China, so it has no right to participate in this organisation meeting."

Lu said that past arrangements had been made thanks to a "consensus" between Beijing and Taipei, referring to former president Ma's willingness to concede that there was only "one China", with each side allowed its own interpretation.

Tsai has never backed that concept, angering Beijing.

"For Taiwan's participation in any international organisation, the prerequisite is the 'one China' principle," Lu said.

Taiwan was a founding member of the ICAO but was thrown out in 1971 when it lost its UN seat to China.

The agency appointed China's Fang Liu as secretary-general last year.

Taiwan's foreign ministry said the ICAO had made the "wrong decision".

"The government expresses strong regret and dissatisfaction," Foreign Minister David Lee told reporters.

Beijing has cut off all official communication with Taiwan since the new government took office.

In another diplomatic snub in July, Taiwanese officials were barred from a UN Food and Agriculture Organization meeting, allegedly due to pressure from China.

The island is one of Asia's busiest aviation hubs, ranking 11th in the world in terms of passenger traffic and sixth for cargo in 2015, according to government figures.

Taiwan 'double agent' gets 18 years for spying for China
Taipei (AFP) Sept 23, 2016 - A Taiwanese court has sentenced a former intelligence officer to 18 years in prison for reportedly working as a double agent and spying for China as relations worsen with Beijing.

Major Wang Tsung-wu was sentenced Thursday by Taiwan's High Court on convictions of engaging in espionage as well as violating national intelligence and security laws.

The court provided no further details, citing national security restrictions.

Local media reported how Wang was allegedly turned by China when he was sent there as an undercover agent for Taiwan's Military Intelligence Bureau around 20 years ago.

He spied for Beijing for more than a decade, reports said.

Wang was recruited by China in 1995 and leaked confidential information before he retired in 2005. He also recruited retired colonel Lin Han in 2013 to help collect intelligence, according to Hong Kong-based Apple Daily.

Lin had travelled to Singapore and Malaysia to meet with Chinese intelligence and passed on information about the identities of the Taiwan bureau's officers and their missions, Taipei-based Liberty Times reported.

Wang was paid around $96,000 while Lin received about $76,000 for the information they passed, it added.

Lin received a six-year jail term for violating national intelligence law, the High Court said.

Both men can appeal the ruling.

It is the latest in a string of espionage cases and comes as ties between Taiwan and China turn increasingly frosty since Beijing-sceptic President Tsai Ing-wen took office in May.

Taiwan and China have spied on each other ever since they split in 1949 at the end of a civil war. Beijing still regards the self-ruled island as part of its territory awaiting reunification, by force if necessary.

In 2011, an army general who headed an intelligence unit was sentenced to life for spying for China, in one of Taiwan's worst espionage scandals.

That sentence came despite a rapprochement between Taiwan and China under then-president Ma Ying-jeou of the Beijing-friendly Kuomintang party.

Earlier this year a mainland Chinese man was jailed for four years for recruiting a former major-general and other local military officers to spy for Beijing.

The major-general received a sentence of two years and 10 months.