(Bloomberg) -- China threatened the leadership of Prague, intensifying a dispute after the Czech capital withdrew from a sister-city partnership with Beijing.

The conflict has been brewing since the upstart Pirate party took over the Prague mayor’s office and took issue with Beijing’s “one China” policy in regards to the sovereignty of Taiwan and Tibet.

The city council withdrew from the sister-city deal, signed in 2016, on Monday, with mayor Zdenek Hrib saying China had refused to remove mention of the policy. The declaration isn’t appropriate for a pact between cities, as it’s rather a matter of national policy, Hrib said.

China’s embassy reacted angrily, saying on Facebook that Prague’s leadership should change its attitude as soon as possible or “it will be their own interests that will be hurt.”

The cancellation, which must still be approved by the city assembly, is “a breach of trust” that hurts ties between China and the Czech Republic, the embassy said, after sending a “serious protest” to the city’s administration.

Read more: China’s NBA Anger Mounts With Canceled Events and Fan Boycotts

The city magistrate’s policy toward China clashes with that of the Czech national leadership, with President Milos Zeman an enthusiastic promoter of Chinese investment in Europe. The Czech Foreign Ministry, which recognizes the one China policy, said the national government wouldn’t get involved.

The dispute erupted last year when China banned several orchestras with “Prague” in their names from performing there after Hrib refused to expel a Taiwanese diplomat from a meeting he hosted.

The Czech capital has long been a bastion of support for Tibet, with late President Vaclav Havel and other politicians hosting the exiled Tibetan spiritual leader Dalai Lama -- to the disapproval of Beijing.

Hrib’s administration restored Havel’s practice of flying the Tibetan flag from Prague city hall. The national government has taken a different stance. with police suppressing peaceful demonstrations during a visit of Chinese President Xi Jinping in 2016 and forcing people to remove Tibetan flags from their homes.

To contact the reporter on this story: Lenka Ponikelska in Prague at lponikelska1@bloomberg.net

To contact the editors responsible for this story: Andrea Dudik at adudik@bloomberg.net, Michael Winfrey

For more articles like this, please visit us at bloomberg.com

©2019 Bloomberg L.P.