KIEV, Ukraine (AP) — Russian hackers are redoubling their efforts in the run-up to presidential elections in Ukraine, according to the head of Ukraine's cyber-police.

Serhii Demediuk said in an interview with The Associated Press that Russian-controlled digital saboteurs are stepping up attacks on the Central Elections Commission and its employees, trying to penetrate electronic systems in order to manipulate information about the March 31 election.

"On the eve of the election and during the counting of votes there will be cyberattacks on certain objects of critical infrastructure. This applies to the work of the polling stations themselves, districts, and the CEC," he said.

"From what we are seeing, it will be manipulation aimed at distorting information about the results of elections, and calling the elections null or void," Demediuk said.

The presidential election will be a test of Ukraine's capacity for order. Russia has consistently portrayed Ukraine under President Petro Poroshenko as corrupt and poorly run, and undermining the election's credibility could serve Russia's propaganda interests.

Ukraine aspires to join the European Union and NATO, and an orderly and credible election could show that it is approaching the democratic standards that those organizations consider key.

Ukraine has been locked in a years-long struggle with Russia-backed separatists in the country's east and has repeatedly been hit by cyberattacks of escalating severity. Since 2014, its energy, transportation and banking systems have been attacked. The malicious program NotPetya hit thousands of computers not only in Ukraine, which was the main target of the attack, but throughout the world.

Asked about Demediuk's claims, Kremlin spokesman Dmitry Peskov said Wednesday: "We know nothing about this. The only thing I can say is that we've been hearing similar statements from different countries in the world. This is becoming a sort of mania or phobia but it has nothing to do with reality. Russia has never had anything to do with any types of cybercrimes."

None of the 44 registered candidates appear to have enough support to win an absolute majority, which would force a runoff three weeks later.

The activity of hackers has noticeably increased during the election campaign six weeks before the elections, Demediuk said. He said some of the hackers are impersonating top officials in order to penetrate the computers of commission members and technical staff.

"Every day cyber incidents that come from Russia or from other countries are increasing. Why from other countries? Because our opponents and enemies are not stupid, they use different methods to anonymize and distort information," he said.

Kiev says the hackers are combining usual digital espionage methods with attempts to manipulate or intimidate.

"We see a combination of classic cyberattacks, such as those previously committed, with misinformation and social engineering," Demediuk said.

In 2015 Ukraine was the site of the world's first confirmed attack on a power system. The hackers succeeded in paralyzing 30 electrical substations and leaving around 230,000 people without power.

Demediuk said malicious Russian software was often tested in Ukraine, then later used in other countries.

"Ukraine is the launching pad where it all begins ... they first of all test us. We are the enemy for them, and they are for us. And so the use of any cyber weapon is a priority. And if it works with us, they then upgrade it to the requirements and infrastructure and use it in this or that country," said Demediuk.

He said Ukraine continues to monitor the activities of the group nicknamed APT28 or Fancy Bear, which the U.S. Department of Justice and a host of independent reports have tied to Russia's military intelligence agency, often called the GRU.

"We follow them, we have indicators with which we can identify and see them. They constantly carry out their activities here," he said.