KYIV — Ukrainian law enforcement officials on Tuesday jailed Oleksandr Dubinsky, a member of parliament who four years ago helped Rudy Giuliani in his failed attempts to dig up dirt on Joe Biden on behalf of then-president Donald Trump.

Dubinsky is accused of treason for allegedly working to help Russia in its war against Ukraine. His arrest restores a spotlight on the efforts by Trump and his associates to gain political advantage by discrediting Biden and his son, Hunter Biden. Trump, despite facing numerous legal prosecutions, is the overwhelming Republican favorite to challenge Biden in next year’s election.

Authorities from the Security Service of Ukraine, or SBU, and the State Bureau of Investigations informed Dubinsky on Monday that a criminal case had been opened against him on charges of state treason, the agencies said in statements posted on the Telegram messaging platform.

The agencies accused Dubinsky, another former member of parliament, Andriy Derkach, and former prosecutor Kostiantyn Kulych of belonging to an organization controlled by Russia’s military intelligence agency, the GRU, which allegedly “carried out subversive informational activities in favor of the Russian Federation.”

“The main task of this organization [was] to destabilize the sociopolitical situation in Ukraine and discredit our state in the international arena,” the SBU statement said. “Perpetrators face up to 15 years with confiscation of property.”

In 2020 and 2021, the United States placed the three men under sanctions after similarly accusing them of links to Russian intelligence services and attempting to interfere in the 2020 U.S. presidential election.

Early Tuesday, a Kyiv court ordered Dubinsky to be detained for “at least 60 days” without bail, the State Bureau of Investigations said.

The statements about the case did not name Dubinsky and referred only to a “current people’s deputy.” However, Dubinsky confirmed the charges on his Telegram channel and insisted that he was innocent.

“I’m to be held in custody until Jan. 12, 2024 — that’s called ‘New Year in a detention facility,’ ” Dubinsky said in a video posted on Telegram following the court decision.

Dubinsky’s group was allegedly created by the GRU deputy head Volodymyr Alekseyev and received some $10 million to carry out its activities, the SBU said in its statement. The agency said Dubinsky worked under the code name “Buratino” — the Soviet-era name for Pinocchio.

“As part of the pretrial investigation, it was documented that the suspect was spreading fakes about the higher military and political leadership of our country,” the SBU said. One of the activities was to “spread of fakes about the alleged interference of Ukrainian high-ranking officials” in the U.S. 2020 presidential elections.

In December 2019, as the House was drafting impeachment charges against Trump, Giuliani, then the president’s personal lawyer, met with Dubinsky and Derkach in Kyiv while working on a documentary on Ukrainian corruption.

The documentary, aired on the far-right One America News network, sought to counter the charge that Trump abused the power of his office when he asked Ukrainian President Volodymyr Zelenskyy during a phone call months earlier to “do us a favor” and launch an investigation into Burisma, the Ukraine gas company where Hunter Biden had served on the board of directors.

Giuliani also hoped to gather material that would implicate the elder Biden, then Trump’s main political rival, in corruption schemes connected to Burisma. However, that trip, and subsequent efforts by Giuliani, failed to produce any credible evidence of wrongdoing by Joe Biden.

Dubinsky and Derkach had held a series of news conferences in Kyiv just before Giuliani’s trip, at which they claimed to reveal corruption at Burisma linked to the Bidens.

In September 2020, the Treasury Department announced sanctions on Derkach for running an “influence campaign” against Joe Biden and said Derkach was “an active Russian agent for over a decade.”

In January 2021, the Treasury Department also imposed sanctions against Dubinsky, Kulych and five others for being part of “a Russia-linked foreign influence network associated” with Derkach.

“Since at least 2019, Derkach and his associates have leveraged U.S. media, U.S.-based social media platforms, and influential U.S. persons to spread misleading and unsubstantiated allegations that current and former U.S. officials engaged in corruption, money laundering, and unlawful political influence in Ukraine,” the Treasury Department said at the time.

Serhiy Morgunov contributed to this report.