Russian news agencies have reported that a powerful explosive device went off late on December 21 in the city of Donetsk, in conflict-torn eastern Ukraine.
The agencies cited authorities in the self-declared separatist region as saying the blast occurred at a bus stop around 7.20 p.m. local time in a residential neighborhood of downtown Donetsk.
There were no immediate reports of any casualties.
Police officers were at the site of the explosion, TASS reported.
Russian-backed separatists control most of Donetsk and the neighboring Luhansk regions, where fighting has taken place between Ukrainian government forces and separatists.
Fighting intensified last month after weeks of relative calm.
On November 14, Ukraine reported the death of five soldiers north and west of Donetsk, the highest military death toll since the latest cease-fire took hold in September.
More than 7,900 people have been killed in fighting in eastern Ukraine since April 2014.