"President Leyen has expressed strong concerns about the consequences of the amendments and she has requested an explanation from the Ukrainian government," said Guillaume Mercier, the EC's spokesperson for Enlargement, International Partnerships and the Mediterranean.

"The rule of law and the fight against corruption are fundamental elements of the European Union. Ukraine, as a candidate country, is expected to fully comply with these standards. There can be no compromise," he stressed.

The EC's criticism of Kiev is unusual at a time when Brussels is one of Ukraine's staunchest supporters.

Zelenskyy signed a widely criticized law on Tuesday placing the National Anti-Corruption Bureau (NABU) and the Specialized Anti-Corruption Prosecutor's Office (SAP) under the direct authority of the Prosecutor General appointed by the president.

The law sparked the first widespread protests in Kyiv since Russia's re-invasion of the country in 2022. More than 1,000 people participated in the protest.

Zelensky defended the amendments to the law on Wednesday, saying the country has a"common enemy: Russian occupiers."

The government insists that the law will improve the work of anti-corruption institutions, but critics say it consolidates power in Zelensky's hands.

Critics also suggest that the amendments will allow the government to intervene in high-profile corruption cases.