The incident took place this afternoon.
"The MLA arrived at the CMO office along with his supporters this afternoon and after locking the door from inside misbehaved with me and threatened me," CMO P N Chaturvedi told reporters.
Singh was mounting pressure to transfer a woman staff in the medical department even after an employee was appointed recently on the recommendation of a senior minister, he claimed.
"The MLA was asking me to ignore the minister's recommendation," the CMO said, adding that he has informed District Magistrate Shubhra Saxena about the incident through a letter and has also demanded proper security for the CMO office.
"The gates and doors of the CMO office were locked by the employees and I was kept there... They also misbehaved with me," the Mallawan MLA said.
Stressing that he wanted to lodge a police complaint against the CMO, Singh said that he will, however, be consulting other MLAs of the district before such a move.