Supporters of the rival camps have clashed in the past
Kiev (AFP) - Ukraine's interior ministry on Saturday called on a comedian tipped to become the country's next president and his incumbent rival not to exacerbate tensions ahead of a run-off in a high-stakes election.
Nerves are starting to fray as polls show the comic and actor Volodymyr Zelensky easily defeating President Petro Poroshenko for the leadership of a country seen as the biggest frontier between Europe and Russia.
After the first round of voting -- in which the 41-year-old political novice outshone the 53-year-old president -- the gloves have come off, with the rivals trading barbs and sparring bitterly on television.
"We are approaching the final phase of the election campaign and the atmosphere in society is tense," Ukraine's deputy interior minister Sergiy Yarovyi said in a statement.
"The mood of open hostility between the candidates is being stoked," he added, calling on both teams and their supporters not to play dirty.
"Do not rock the boat ahead of the second-round of voting."
This week police launched a criminal probe after a video emerged online of Zelensky being hit by a truck.
The video ended with a line of white powder -- possibly cocaine -- being snorted through a rolled-up bank note, an apparent allegation of drug abuse.
Zelensky's campaign pointed the finger at Poroshenko's team, which has denied involvement.
- Trading insults -
In a testy phone exchange between the rivals broadcast live on television this week, Zelensky refused to debate Poroshenko before next Friday, repeatedly interrupting him.
He then hung up on the Ukrainian president, leaving Poroshenko speechless.
Many were taken aback at the sight of a humiliated leader, with his long-time rival Yulia Tymoshenko recording a video address.
"While fighting for the right to become president , do not destroy the honour and pride of the status of the president," said the former prime minister, who came third in the first round of voting.
"It's necessary to remain human," she added.
Poroshenko has called his rival a "clown" and a "puppet" of oligarch Igor Kolomoysky, who owns the channel that broadcasts the entertainer's shows.
Support for the comedian among voters has doubled to 61 percent since he won the first round on March 31, according to the Rating pollster.
Poroshenko garnered 24 percent, in a sign that Ukrainians are fed up with mainstream politics, war with Kremlin-backed rebels, poverty and corruption.
Both men have also undergone drugs tests at Zelensky's insistence to prove they do not have a substance abuse problem.
Ukraine's leader has been eager to spar with Zelensky and suggested they hold a policy debate on Sunday.
Zelensky said he was ready to face off with Poroshenko at the country's largest stadium on April 19, two days before the run-off vote.