The protest continued till night as the Delhi University Teachers' Association (DUTA) president Rajib Ray said they would not move till the Vice-Chancellor heard their demands.
Rajesh Jha, a professor associated with the Congress-backed teacher's body Academics For Action and Development (AAD), said the teachers resolved to resist and thwart "the destructive design" of the university administration led by Vice-Chancellor Yogesh Tyagi.
Through the August 28 letter, the university administration replaced 5,000 teachers without any amendment to the University EC resolution of 2007.
Jha claimed due to this letter teachers had been deprived of salaries for several months. "The teachers have worked for months without salary because no one expected this letter to drop in and take away their jobs," Jha said.
Jha said the 2007 resolution had considered ad hoc services as integral part of teaching learning process of the university.
Rasal Singh, who is associated with the National Democratic Teachers' Front (NDTF), said, "There should be justice with teachers. Their demands are justified. There had be no appointments and promotions for last one decade."
The strike might affect the ongoing examinations as the DUTA has also urged teachers to stay away from exam duties.
The DUTA has also written to the University Grants Commission (UGC) and the HRD Ministry on Tuesday to intervene to end the crisis created by the August 28 letter.
It also urged teachers to stay away from invigilation, evaluation and any other official duties.
( With inputs from IANS )