Nearly two dozen lawmakers from Congress and TDP had joined TRS after 2014 Assembly elections.
In a setback to opposition Congress in Telangana, two of its legislators on Saturday announced that they were joining the ruling Telangana Rashtra Samithi (TRS).
Rega Kantha Rao and Athram Sakku, who are both tribal lawmakers, released a statement saying they were joining the TRS as the government was taking several steps for the welfare of tribals. They said if necessary, they would resign from the assembly.
Mr Kantha Rao and Mr Sakku represent Pinapaka and Asifabad constituencies, both reserved for Scheduled Tribes.
The Congress received the jolt ahead of March 12 elections to five seats of the Legislative Council. The resignations will reduce the party's tally in 119-member Assembly to 17, dashing its hopes of winning at least one seat.
This is the first defection to the TRS from Congress after December 7 assembly elections in which TRS was swept back to power, winning 88 seats.
Meanwhile, a lawmaker from Telugu Desam Party (TDP) also called on Chief Minister and TRS President K Chandrashekhar Rao on Saturday. Sandra Venkat Veraiah, who is one of the two TDP members in the Assembly, is also likely to switch sides to the TRS.
Nearly two dozen lawmakers from Congress and TDP had joined TRS after 2014 Assembly elections.