An armed clash between two Ukrainian police units, unaware of each other's presence in an operation against a robbery gang near the capital Kiev, has left five officers dead in the friendly fire.

Ukrainian deputy and advisor to the Ukrainian interior minister, Anton Gerashchenko, announced on his Twitter account that police came up with a plan to crack down on a gang involved in robberies in Kiev and its surrounding region.

Acting upon the information that the gang will target a house in Kniazhychi village near Kiev, the police dispatched a special operations unit to the area. Two undercover cops were also placed to an empty building under construction next to the targeted house to track down the suspects.

An alarm system was installed in the empty building, and regular police units arrived in the scene as the alarm went off and detained the undercover cops.

When the special operations unit arrived on the scene, they saw that two cops were being taken inside a van, causing them to think the gang arrived in the area first and were trying to take the undercover cops as hostages.

The subsequent armed clash between the two police units left five police officers dead, including one from the heavily armed special operations unit.

Meanwhile, three suspects from the robbery gang were detained elsewhere trying to flee into Kiev.