New Delhi, Jun 28 (PTI) P A Sangma today claimed tribal leaders cutting across party lines are unitedly behind him and took potshots at Congress for not standing by his candidature for the President's post despite enjoying the support of tribals for decades. "I only want to express that tribals in India have all along stood by Congress party. We had expected that Congress party would welcome and consider a tribal as its candidate," Sangma said, maintaining that Congress President Sonia Gandhi did not even give him an appointment for which he waited for three days. "Many political parties have positively responded to our (Tribal Forum of India) request. But the largest political party with whom tribals have stood all along--the Indian National Congress--did not come out to support the cause of tribals. They will know the effect of this action," he said. The former Lok Sabha Speaker claimed tribals in India "are united today and we will move in future together with tribal unity which has never been seen before in India." Sangma appealed to MPs and MLAs to vote according to their conscience and claimed that there will be cross voting in his favour. "Today is the victory of tribal unity that a tribal is filing his nomination for President of India's post," he said. Sangma said that he would file his papers as a candidate of the Tribal Forum of India with Odisha Chief Minister Naveen Patnaik and his Tamil Nadu counterpart J Jayalalithaa having nominated him. He is backed by BJP and some of its NDA allies.