A Ukrainian court will today (Monday) September 16, consider opposition lawmaker Aleksandr Dubinski’s lawsuit, alleging President Vladimir Zelensky has illegally extended his term beyond its May 20 expiration.

Dubinski, in custody since November and facing charges that include high treason, argues that Zelensky’s actions violate the Ukrainian constitution.

He originally filed the lawsuit in June, urging parliament to call a presidential election, RT reports.

The presidential election, initially set for March 31, was indefinitely postponed due to martial law imposed amid Ukraine’s conflict with Russia. The court previously postponed the case until September 16.

This development highlights tensions within Ukraine’s political landscape amid the ongoing conflict with Russia.

In a post on his Telegram channel in July, as reported by RT, the lawmaker wrote: “I have to state – there is only one citizen and member of parliament in Ukraine that has taken steps to preserve the constitutional order… it is non-attached MP Dubinski.”

Earlier that month, the prosecutor general’s office launched a fourth criminal probe into the politician over his failure to file tax returns while in custody.

Last November, the Security Service of Ukraine charged Dubinski with high treason over his alleged “information-subversive activities in the interest of Russia.”

The lawmaker has dismissed the accusations, along with two other charges against him, as politically motivated.

Earlier this month, Kremlin spokesperson Dmitry Peskov said that “de jure President Zelensky now is not the legitimate president” of Ukraine. His comment echoed those made earlier by Russian President Vladimir Putin.

Speaking at the St. Petersburg International Economic Forum (SPIEF) in early June, the Russian head of state suggested that presidential powers should have been transferred to the Ukrainian parliament following the expiry of Zelensky’s five-year term in office.

By remaining at the helm, the Ukrainian leader appears to be in breach of “Article 109 of Ukraine’s Criminal Code, which says that this should be treated as seizure of power,” the Russian president argued at the time.

Putin went on to claim that Ukraine’s Western backers were keeping Zelensky in power with a view to blaming him for upcoming “unpopular decisions,” such as lowering the “mobilization age to 18.”

“I think the US administration will force the leadership of Ukraine to make these decisions… and then will get rid of Zelensky,” the Russian president predicted.