"As part of the protest, the faculty members wore black badges whole day and gathered outside the Director's office in the afternoon," a FAAIIMS member said.
The FAAIIMS in its general body meeting also decided to contribute money to help Kumar in his legal fight against the administration.
AIIMS administration has said Kumar had several complaints against him, including for using objectionable language during ward assessment and bad behaviour with patients.
AIIMS had terminated Kumar's services on January 10 for allegedly misbehaving with and manhandling a patient in September last year.
A committee, set up after the incident under the department head S K Sharma, last week took the decision to terminate Kumar's contract with AIIMS.
Earlier, a doctor associated with FAAIIMS said, "Only seven faculties have been terminated till now in the history of AIIMS, but that was also because they went abroad and did not respond to the communication by the institution about their return.