The party asked the two leaders to explain reasons for supporting a "scam-tainted" government at the Centre.
"It is obvious that the UPA government is dangling the sword of the CBI probe against Mulayam and Mayawati into corruption charges against them to coerce them to support it," BJP spokesperson Syed Shahanwaz Hussain told reporters here.
More than the government, the onus was on the BSP and SP chiefs to explain the paradox behind opposing the FDI in multi-brand retail on one hand and supporting the central government on the other, he said.
"It will be appropriate if Mulayam and Mayawati explain their stand on the reasons that compel them to continue supporting the scam-tainted Congress-led government at the Centre," Hussain said.
The BJP leader claimed that the UPA government would fail to last its full term despite adopting "carrot and stick" policy to keep the allies together and predicted mid-term polls sooner than expected.
The BJP's 'Hunkar (clarion call) Rally' in Patna on April 15 next would sound the death knell of the UPA government and elections might take place after that, he said, adding, his party was fully prepared for the polls.
Hussain asserted that the BJP-led NDA would form the next government at the Centre as the prevailing public mood was for NDA's return to power.
He said BJP would support TMC chief Mamata Banerjee if she went ahead with a no-confidence motion in Parliament during the winter session.
SP and BSP together account for 43 members in the Lok Sabha. The Trinamool Congress, which parted ways with the UPA on the FDI issue, has 19 members.
