Agartala, Aug 23 : In a setback for the opposition Congress in Tripura, its working president and former minister Billal Mia resigned from the party on Wednesday. Mia, a leading Muslim leader of the party in Tripura, said in a letter to Congress President Mallikarjun Kharge that he wants to quit from all posts and the primary membership of the party, which was his home for more than 40 years . Though the 63-years-old leader did not cite any reason for his resignation, Mia recently came into close contact with the leaders of the ruling BJP. He was annoyed, according to the local media, for not being nominated by the Congress in the February 16 Assembly polls and in the September 5 by-election to the Boxanagar Assembly constituency, a Muslim dominated seat. On the other hand, Tripura Pradesh Congress President Asish Kumar Saha expelled Mia from the party for six years for 'anti-party' activities. /IANS