Acknowledging that the UPA will be called by the President to form the next government, she said that BSP has taken the decision keeping in view the present situation and its objective of keeping BJP out of power.
The BSP supremo said that on the day the results, she had telephoned Prime Minister Manmohan Singh and Congress President Sonia Gandhi and congratulated on the UPA victory.
The Prime Minister, Mayawati said, called her on Sunday evening seeking her party's positive approach towards strengthening secular forces.
She said the party's National Executive and Parliamentary Board met this morning and discussed these issues before deciding on giving unconditional support to the new government from outside.
In the elections, the UPA coalition got 261 seats just 11 short of the magic figure of 272 required for an absolute majority in the 543-member Lok Sabha. Of this Congress alone got 206 seats.
Apart from BSP, the JD(S) has also announced support of its three MPS.
The RJD and SP, which fought Congress in the elections, have backed the new government. The RJD has four MPs while the SP has 23 MPs.
Mayawati claimed that terming her as sister, the Prime Minister had asked her to take a positive approach on strengthening secular forces and formation of a secular government at the Centre.
She said party general secretary and her close confidant Satish Chandra Mishra will hand over the letter of support of the BSP to President Pratibha Patil and UPA chairperson Sonia Gandhi.
At the same time, the Uttar Pradesh Chief Minister said that the Centre will not help the state government with financial assistance.