Singh, at a rally in Kochi last week, urged the Left parties to stand by the Congress in its fight against the BJP.
The senior Congress leader said, "If they (the Left parties) are sincere in the fight against the BJP and its anti-people policies, they have to cooperate with the leadership of the Congress at the national level and fight together against the BJP's misrule and divisive politics."
"The Congress claims it is their policies the BJP is implementing. In both Kerala and Tripura (where the Left is in power), the Congress is helping the BJP against the Left. On specific issues against the toxic communal politics of BJP-RSS, we are cooperating with all those secular forces fighting the BJP-RSS," Karat told PTI.
Singh earlier claimed that the country's economy slowed down due to "hasty" implementation of the Goods and Services Tax (GST) soon after demonetisation by the NDA government, and said he did not see "any immediate recovery in sight".
Asked if real estate, petroleum, electricity and alcohol should be brought under the GST, she said since such proposals directly affect revenues of the states which are already stressed due to "bulldozed centralisation of resources under the Modi regime", the states have to be consulted "unlike the formal and nominal consultation at present".