The CPI Friday said it was a "historical necessity" to build a powerful anti-BJP nation-wide platform to defeat the saffron party at the hustings.
Communist Party of India general secretary Suravaram Sudhakar Reddy also said Congress was the main opposition party in the country and without it, there cannot be a strong opposition.
"I am not defending (Congress)...I have several differences with the Congress and its policies.
But, today the most important point is to defeat communalism, to defend the Constitution, to defend secularism and for these reasons for the time being we think there is a necessity to build a powerful anti-BJP nation-wide platform.
It may not be a front some parties may be in the front and some parties may be outside but there is a necessity that is a historical necessity and anybody trying to wreck it is working on behalf of BJP," Reddy said.
He expressed confidence that the BJP would be defeated in the 2019 general elections and a strong opposition platform built across the country.
Reddy flayed Prime Minister Narendra Modi for his attacks on the Opposition parties and the proposed opposition 'front.'
Hitting back, he asked Modi "Why did you build a front."