Electromechanical lock. Actuator (103) comprises drive head (109) rotatable by electric power (160). Access control mechanism (104) comprises driven gear (101) with cogs, and grip mechanism (111). Drive head (109) comprises two pins (210, 212) configured and positioned so that one of pins (210, 212) is in notch between two cogs (220, 222, 224, 226, 228) of driven gear (101). For opening, drive head (109) rotates driven gear (101) to open position (400), by two pins (210, 212) driving cogs (220, 222, 224, 226, 228) and overcoming grip mechanism (111), and thereby setting access control mechanism (104) to be rotatable (152) by user. If external mechanical break-in force (172) is applied, drive head (109) remains stationary by at least one of pins (210, 212) contacting at least one of cogs (220, 222, 224), and by grip mechanism (111) holding driven gear (101) stationary in locked position (200).