European Council President Donald Tusk | Valda Kalnina/EPA Tusk likens Polish government policy to ‘Kremlin’s plan’ Twitter intervention in Polish fuels talk of a presidential run in 2020. Szydło calls it an attack on Poland.

European Council President Donald Tusk issued a sharp attack on the Polish government, fueling anew speculation about his political future back home.

In tweet in Polish sent on Sunday, the former Polish prime minister offered a litany of charges against his political rivals in the ruling right-wing Law and Justice government, likening them to Vladimir Putin's Russia.

It is unusual for the Council president to criticize any EU state, since his job is to represent the member countries' interests in Brussels. But Tusk and the PiS government have a long and bitter history. Warsaw tried but failed to block Tusk's reappointment earlier this year.

Poland's rulers are also fighting with Brussels over its moves to exert more control over the judiciary and the media. The European Commission has begun legal action against Poland, citing concerns about the rule of law.

"Alarm! Harsh dispute with Ukraine, isolation in the European Union, departure from the rule of law and courts independence, attack on the NGO sector and free media -- is this a Law and Justice strategy or the Kremlin's plan? Too similar to sleep peacefully," Tusk said in his tweet.

Alarm! Ostry spór z Ukrainą, izolacja w Unii Europejskiej, odejście od rządów prawa i niezawiłości sądów, atak na sektor pozarządowy i wolne media - strategia PiS czy plan Kremla? Zbyt podobne, by spać spokojnie. — Donald Tusk (@donaldtusk) November 19, 2017

Polish Prime Minister Beata Szydło replied to Tusk, tweeting in Polish that as president of the Council, Tusk has "done nothing for Poland. Today, in exploiting his position to attack the Polish government, he attacks Poland."

@donaldtusk jako @eucopresident nic dla Polski nie zrobił. Dzisiaj, wykorzystując swoje stanowisko do ataku na polski rząd atakuje Polskę — Beata Szydło (@BeataSzydlo) November 19, 2017

Tusk's current term ends in 2019, a year ahead of presidential elections in Poland. As former leader of the center-right and longtime head of government, Tusk is often mentioned as a possible candidate.

Sunday's intervention isn't the first time Tusk has publicly sparred with the Polish government. In June, he criticized Szydło for invoking the Holocaust to defend her opposition to immigration. He has also opposed the country's judiciary reforms.

This article was updated to include Szydło's response.