Ukraine called for an investigation Thursday after one of its citizens was shot dead by Russian border guards while allegedly attempting to enter the country illegally.

A native of the Kharkiv region, which borders Russia, was shot dead by a patrolmen in the early hours of Thursday morning as he tried to race across the border in a car with a trailer attached, Interfax reported.

Investigative Committee spokesman Vladimir Markin defended the border patrol’s response. “From preliminary reports … the border guard acted in accordance with the law on protecting the state frontier,” he said.

Border guards used a flare gun to signal to the driver of a white Neva car with Ukrainian plates, he said.

“In response, the car accelerated,” Markin said. Guards then blocked the road and sent more flares.

“The driver was forced to turn around, and tried to return to Ukrainian territory. A senior border guard took measures to stop the driver, but the driver switched on his headlights, accelerated, and drove directly at the border guard,” Markin said. “The senior guard then fired a warning shot into the air. The guard was knocked to the ground when he was hit by the car, and he fired into the car as he fell.”

The driver, identified as 38-year-old Alexander Yanimenko, was shot in the neck and died instantly. A search of the car’s contents revealed “marine equipment,” Interfax reported.

The incident threatened to spark renewed tensions between Russia and Ukraine.

“It is certainly an exceptional event for the two countries, which, regardless of the circumstances, causes some tension said Oleg Voloshin, press secretary at the Ukrainian Embassy in Moscow.

“Not so much between the governments, but between the peoples of both nations,” he said. “The death of a Ukrainian citizen on the Ukrainian-Russian border is certain to affect the Ukrainian public, and we hope that there will be a thorough investigation into this tragedy.”