The meeting between the two leaders comes against the backdrop of Rao calling on Congress vice president Rahul Gandhi early today and his meeting with Congress chief Sonia Gandhi.
"I had a meeting with Rao. We had preliminary discussions on the relationship between TRS and Congress, as he had committed that once Telangana state is created, he is prepared to merge his party," Singh told reporters here.
Queried about the status of the talks between the two parties, he reiterated that it was "preliminary."
Rao had met Sonia Gandhi yesterday sparking speculation of the merger of two parties after Parliament passed the Andhra Pradesh Reorganisation Bill, approving the creation of a separate Telangana state.
Singh, who is in-charge of Andhra Pradesh affairs of the party, said new Pradesh Congress Committees would be constituted soon for Seemandhra and Telangana.
According to Congress sources, central in-charges of the party are holding discussions with leaders from both the regions for constituting the committees.
"We are in consultation with leaders from both the regions for preparing two panels for the States. After the process is completed, it would be sent to the approval of the top leadership," a Congress leader said.
Those in charge of Congress affairs in Andhra Pradesh are expected to meet tomorrow as well to conclude the list of leaders to be nominated for various positions in Seemandhra and Telangana regions.
Andhra Pradesh PCC president Botcha Satyanarayana was also present in the meeting, party sources said.