The Ukrainian army is locked in a conflict with breakaway fighters in Donetsk and Lugansk.
A volley of shots has been fired at a car carrying a principal aide of Ukraine’s president, in what a senior official called an assassination attempt.
More than 10 bullets hit the car during Wednesday’s attack near the village of Lesnyky, about five kilometres (three miles) outside the capital Kyiv, a police statement said.
The vehicle’s driver was wounded in the incident.
The police statement said a criminal case on suspicion of premeditated murder had been opened.
A senior legislator representing President Volodymyr Zelenskyy’s Servant of the People party said the aide, Serhiy Shefir, was not hurt. Shefir, 57, is one of the officials closest to the president and leads a group of advisers.
“I briefly spoke to him, everything is fine, he is alive and well,” Davyd Arakhamia was cited by Russia’s RIA Novosti news agency as saying.
Zelenskyy denounces act of ‘weakness’
Zelenskyy, who came to power promising to take on the country’s oligarchs and fight corruption, is currently in the United States attending the UN General Assembly.
He said he did not know who was responsible for the attack, but vowed to continue with his planned reforms despite the incident.
This week, the Ukrainian parliament is due to debate a presidential law directed at reducing the influence of oligarchs.
“Sending me a message by shooting my friend is weakness,” Zelenskyy said.
“It does not affect the strength of our team, the course that I have chosen with my team – to change, to clean up our economy, to fight crime and large influential financial groups.
“This does not affect that. On the contrary, because the Ukrainian people have given me a mandate for changes.”
Interfax Ukraine quoted Zelenskyy adviser Mykhailo Podolyak as saying: “We, of course, associate this attack with an aggressive and even militant campaign against the active policy of the head of state.”
Podolyak told Reuters the “open, deliberate and extremely violent assault with automatic weapons cannot be qualified any differently than as an attempted killing of a key team member”.
Kremlin denies involvement
Oleksandr Korniienko, head of Zelenskyy’s political party, suggested possible Russian involvement in the attack.
“A Russian trace should not be absolutely ruled out. We know their ability to organise terrorist attacks in different countries,” Korniienko told reporters.
Kremlin spokesman Dmitry Peskov said such that assessment had “nothing to do with reality”.
Tensions between Kyiv and Moscow have escalated in recent years following Russia’s annexation of the Crimean Peninsula in early 2014 and the Kremlin’s backing of separatist forces battling Ukrainian troops in the Donbas.
The rebels seized a swath of territory in the region in April 2014, weeks after Moscow seized the Black Sea CrimeanPeninsula.