Officers of the Nigeria Police Force and workers at the National Health Insurance Scheme (NHIS) head office in Abuja clashed on Monday morning.
The workers had blocked the entrance of the building in protest against the coming to work of suspended Executive Secretary, Usman Yusuf.
But Yusuf, escorted by policemen, forced his way in, despite his suspension last week by the NHIS governing council.
Yusuf had kicked against his suspension by the board, saying he would resume work on Monday nonetheless. The NHIS workers union then threatened to lock him out of office if he dares to show up.
But Yusuf arrived at 8:30am, gained entry into the premises with the aid of the policemen.
Policemen on ground also teargassed the workers in the enduring fracas.