A handheld power tool (1) comprising a tool (8), a motor (2) configured to power the tool (8), an actuator (3), a control arrangement (21), and a connector portion (5) configured to receive a pole connector portion (15) of a pole extension unit (10) for increasing the reach of the power tool (1). The power tool (1) comprises a safety switch (9) configured to switch from a first state to a second state when a pole connector portion (15) is attached to the connector portion (5) of the power tool (1). The control arrangement (21) is configured to prevent a control of operation of the motor (2) based on input from the actuator (3) when the safety switch (9) is in the second state. The present disclosure further relates to a pole extension unit (10) and power tool assembly (20) comprising a handheld power tool (1), and a pole extension unit (10) for increasing the reach of the power tool (1).