Canada will never accept the results of "sham" annexation votes organized by Moscow in the Russian-occupied regions of Ukraine, and will sanction those complicit in the referendum effort, Prime Minister Justin Trudeau said Wednesday.

The Canadian leader said in a Twitter message that he'd spoken with Ukraine President Volodymyr Zelensky and told him that "Canada will never recognize Russia's 'referendums.'"

He also pledged Ottawa's steadfast support for Kyiv "with military, humanitarian, and financial assistance."

In a statement he said Ottawa will impose new sanctions "against persons and entities that are complicit in this latest attempt to undermine the principles of state sovereignty," which he described as a "further escalation" in the conflict by Moscow.

Kremlin-installed authorities in the four Ukrainian regions under Russian control on Tuesday claimed victory in the votes, saying that preliminary results show a majority in favor of being annexed by Moscow.

The leaders of Ukraine's Lugansk, Kherson and Zaporizhzhia regions on Wednesday called on President Vladimir Putin to formally annex the territories into Russia.

Only Donetsk -- which along with Lugansk make up the industrial Donbas region and have been partially controlled by pro-Kremlin separatists since 2014 -- had yet to formally ask Putin for annexation.

Earlier, Trudeau called the votes "illegitimate" and a "sham," and decried Moscow's "attempted, illegal annexation of Ukrainian territories."

"Let me be clear: Ukraine's borders will not change. Ukraine's territory will remain Ukraine's," he said.