An early-morning blast on a residential street in Bucha, just outside Kyiv, left two police officers with limb injuries after a second explosion detonated as officers responded to the scene.
Authorities have described the incident as an act of terrorism and say a 21-year-old local has been detained in connection with the two blasts.
He has been formally charged with terrorism.
Police say the suspect was recruited online to plant the devices, and investigators are still working to identify who directed him.
A security source told the BBC the contact was made through the game World of Tanks, though officials have not publicly confirmed the platform.
Investigators say the man was offered about 25,000 hryvnias for each explosion — roughly £450 or $570.
In footage released by police, the suspect claims he was coerced and threatened with harm to his mother, including being watched from a drone, if he refused to carry out the attacks.
Ukraine’s security service (SBU) has labelled the suspect a Russian agent, but police cautioned that links to Russia are still being established as part of the probe.
The injured officers suffered wounds to their limbs that are not believed to be life-threatening.
Neighbours described a powerful blast and a shock wave that rattled the area, and emergency crews quickly arrived on the scene.
The Bucha explosion follows a string of similar incidents across Ukraine this year.
In late February, a bomb in Lviv killed a police officer and injured more than 20 people; authorities said the device had been planted by a Ukrainian woman allegedly paid by Russian intelligence.
Other attacks in Mykolaiv and Dnipro around the same time also targeted law enforcement.
Police say the investigation into who organised the Bucha blasts is ongoing as they attempt to trace online contacts and any wider networks behind the attacks.
