Sparking immediate worries that violence could once again spike in Ukraine, the Kiev government's military claimed Friday that a convoy of Russian tanks, artillery units, and other vehicles crossed the country's eastern border.

According to Andriy Lysenko, a spokeperson for the Kiev army, a column of 32 tanks, 16 howitzer artillery systems, and trucks carrying ammunition and fighters has crossed into eastern Ukraine from Russia.

"The deployment continues of military equipment and Russian mercenaries to the front lines," Lysenko said in a televised briefing in which he said the crossing occurred on Thursday.

As the Associated Press notes, Lysenko "provided no specific evidence or timetable, and it wasn't immediately clear how his agency had obtained the information since parts of Ukraine's eastern border with Russia have been under rebel control since August." Despite the lack of evidence, the nature of the claim—coupled with recent fighting in the eastern regions—has sparked real worries that a peace deal reached in September may be eroding faster or more completely than previously thought.

Despite those flare-ups of violence that have allowed the conflict to simmer, a full-scale breakout of violence has not happened since the agreement was reached.

As Reuters reports:

The report of a new Russian movement of armor across the border follows a charge on Thursday by pro-Russian rebels in eastern Ukraine that Kiev government forces had launched a new offensive - which Kiev immediately denied.

Sporadic violence has continued since a Sept. 5 truce in a conflict that has cost over 4,000 lives.

Tensions have steadily increased this week following local elections held in eastern regions of the country, where many Ukrainians continue to refuse the full authority of the government in Kiev. Russia was accused of backing the election results, while Kiev flatly rejected their legitimacy. Clarifying Moscow's position on Friday, presidential aide Yury Ushakov said that Russia was careful to say that it "respected" the vote of the people in eastern Ukraine. He pointed out that "recognized" is a different word.

"The word 'respect' was chosen on purpose," Ushakov stressed, according to Russian news outlet Ria Novosti.

Despite those claims, violence has spiked in recent days. As The Guardian reports:

Fifteen civilians were wounded by shrapnel in Donetsk, the mayor’s office said, in a night of shelling in two neighbourhoods near the ruins of the airport, where government troops are holding out.

Some 150 mourners later attended an emotional memorial service in the city for two teenage boys killed when a shell hit a school playing field on Wednesday. Kiev and the insurgents blamed each other for the incident.

Claims of fresh troop movements are reinforcing fears of a return to all-out fighting.