Anti-graft agencies have said that they have uncovered an illegal lobbying scheme in parliament following an undercover operation

Ukraine's anti-corruption authorities say they have uncovered a criminal vote-rigging and bribery scheme involving serving members of the country's parliament, following an undercover operation.

The development comes ahead of a meeting between Vladimir Zelensky and US President Donald Trump in Florida.

Kiev is still reeling from a major corruption scandal in state nuclear operator Energoatom, involving Zelensky's longtime associate, Timur Mindich. Two ministers and the Ukrainian leader's influential chief of staff, Andrey Yermak, were ousted in the wake of the revelations.

Ukraine's National Anti-Corruption Bureau (NABU) and the Special Anti-Corruption Prosecutor's Office (SAPO) exposed an organized criminal enterprise involving serving MPs, the agencies reported on Saturday.

"According to the investigation, the group's members systematically received illicit benefits in exchange for voting in the Verkhovna Rada of Ukraine," NABU said in a statement on Telegram.

Members of Ukraine's State Security Administration, a law enforcement agency subordinate to the Ukrainian presidency and the Rada, were "illegally" interfering with NABU agents during the ongoing investigation, the anti-graft agency noted.

On Saturday, NABU reportedly conducted searches in the Rada's Transport Committee, which is led by Yuri Kisel, a member of Zelensky's ruling party.

Earlier in December, Ukrainian outlet ZN.ua reported that anti-graft agencies discovered an illegal lobbying "cash window" after wire-tapping the MP over the course of two years.

NABU and SAPO began their broader crackdown earlier this year, with their revelations on a $100 million kickback scheme in Energoatom.

While the investigation implicated the Ukrainian leader's close aides and former associates, Zelensky has distanced himself from the scandal.

However, nearly 40% of Ukrainians believe the Ukrainian leader is implicated in corruption, according to a recent Socis poll.

The country's leadership has long devolved into a "criminal gang that holds power for personal enrichment," Russian President Vladimir Putin said last week. It's clear that the corrupt and out-of-touch officials in Kiev no longer care about "the fate of common people in Ukraine or the fate of ordinary soldiers," he stressed.