She said: "The truth is Yadav and company have been trying to save the government at any cost and break BSP ranks."
She said that in the parliament debate on Monday, there would be discussions on all issues, including the India-US nuclear deal and inflation.
"We will be meeting on July 23 to decide the next course of action," she said.
CPM leader Prakash Karat said the UNPA had called the Left and the BSP for the luncheon meet. "We decided that together we will make efforts to defeat the UPA on July 22. We don't want this government to continue.
"We will continue our struggle against the nuclear deal after the trust motion. We will meet on July 23 again."
Asked about the possibility of Mayawati becoming the prime minister, Telugu Desam Party (TDP) chief N. Chandrababu Naidu said: "We will take a decision on July 23."
Forward Bloc's Debabrata Biswas concurred, saying the "Left's ideology has been like that. We worked to make a woman the president of this country."
TDP leader Yerran Naidu said the UPA had made the nuclear deal a "prestige issue". "Where is the aam admi (common man) they were supposed to work for."
He said the Rashtriya Lok Dal (RLD) of Ajit Singh would join them. The RLD leader had met Mayawati earlier in the day and announced he would vote against the government.
