China’s foreign ministry said on Friday it had imposed sanctions on Lithuanian Deputy Transport and Communications Minister Agne Vaiciukeviciute for visiting Taiwan, the latest development in Beijing’s diplomatic row with the European Union country.

The foreign ministry said China would also suspend engagement with Vaiciukeviciute’s ministry and cooperation on transportation with Lithuania, a small Baltic republic.

Lithuania’s Ministry of Transport and Communications said it regretted China’s announcement.

“Beijing is choosing to continue and intensify the course of illegal actions against (an) EU member state,” the Lithuanian ministry said in a statement to Reuters.

“This is not only not conducive to the development of China’s relations with the democratic world, but also reverses Beijing’s own declared policy so far of not hindering the development of a mutually beneficial relationship with Taiwan, one of the world’s most progressive economies.”

China claims self-ruled Taiwan as its territory and is against foreign politicians visiting the island. Democratically governed Taiwan rejects China’s claim.

Lithuania’s recent bolstering of relations with Taiwan has infuriated Beijing and led to a fall in Lithuanian exports to China in the first quarter of this year to almost zero.

Vaiciukeviciute said on Twitter on Friday that she had visited three cities and two seaports and had 14 meetings in Taiwan over a five-day period.

“A productive week in Taiwan, looking for more ways of LT Transport cooperation with TW maritime, shipping and aviation companies,” she tweeted, referring to Lithuania and Taiwan by their abbreviations.

Vaiciukeviciute visited Taiwan days after U.S. House of Representatives Speaker Nancy Pelosi did so. In response to Pelosi’s visit, China launched massive military drills around Taiwan, slapped sanctions on Pelosi and trade restrictions with Taiwan.

When Jovita Neliupsiene, Lithuania’s vice minister of the economy and innovation, visited Taipei in June, she said Lithuania planned to open a representative office in Taiwan in September.

Lithuania has come under sustained Chinese pressure to reverse a decision last year to allow Taiwan to open a de facto embassy in the capital Vilnius under its own name.

China has downgraded diplomatic relations with Lithuania and pressured multinationals to sever ties with it.

In January, the EU launched a challenge at the World Trade Organization accusing China of discriminatory trade practices against Lithuania and arguing that this threatened the integrity of the bloc’s single market.

China said that it has always abided by WTO rules and that its problem with Lithuania is political, not economic, in nature.