Pro-Russian separatists in Ukraine's eastern region of Donetsk have announced the end of a ceasefire, ending a period of relative calm as the country braces for parliamentary polls.

Addressing reporters on Thursday, the prime minister of the self-proclaimed Donetsk People’s Republic, Alexander Zakharchenko, said "The truce has been observed by us alone. But the day before yesterday we started to respond as well. It has been quieter since yesterday." 

He added that self-defence forces are planning to retake the cities of Slavyansk, Kramatorsk and Mariupol, while Kiev prepares for legislative polls scheduled for Sunday.

“Periods of intense hostilities will follow. We will retake Slovyansk, Kramatorsk and Mariupol. Unfortunately, it was impossible to make peaceful settlement the focus of negotiations. We are the only ones who comply with the regime of silence,” he said.

Meanwhile, Ukrainian Prime Minister Arseny Yatseniuk warned of possible attempts by Russia to destabilise the parliamentary election and ordered security to be boosted to prevent "terrorist acts" being carried out.

"It is clear that attempts to destabilise the situation will continue and be provoked by the Russian side. They did not succeed during the presidential election [in May] but their plans have remained," he told a meeting of top security chiefs and election monitors.

"We need full mobilisation of the whole law-enforcement system to prevent violations of the election process and any attempts at terrorist acts during the elections."

Sunday's polls

The breakaway leaders in the east have not allowed elections to take place in the territory they control, Al Jazeera's Barnaby Phillips reported from Kiev.

Describing the political situation in the country as "fraught," our correspondent said "a lot of accusations are being fired at President Poroshenko for his handling of the war, and the feeling that he was, perhaps, too soft on the seccionists, as well as a deteriorating economic situation.

"There are many disappointments, particularly here in Kiev, among people who were responsible for the overthrow of President Viktor Yanukovich last February in what they saw as a revolution. The pace for political social change has not been fast enough since."

Fighting in the eastern part of the country has claimed nearly 3,000 lives since it erupted following the unseating of Russia-backed Yanukovich.

Violence has decreased since pro-Moscow fighters and Kiev signed the ceasefire, known as the Minsk memorandum, on September 19. 

Source: Agencies