Guwahati, April 23 : Within a week after Ripun Bora joined the Trinamool Congress, party supremo Mamata Banerjee has appointed him as the president of Assam unit. Following his appointment to the new position, Bora on Saturday tweeted: "My gratitude to Trinamool Congress chairperson Mamata Banerjee and general secretary Abhishek Banerjee for showing faith in me and appointing me as the state president. I will continue to work for the betterment of our state with the best of my ability." Bora -- a former Assam state Congress president, and ex-Rajya Sabha member, along with his wife and former Congress MLA Monika Bora and son on April 17 met Trinamool Congress' General Secretary Abhishek Banerjee in Kolkata and joined party. Before joining Trinamool Congress, Bora sent his resignation letter to Congress chief Sonia Gandhi, saying that a section of Congress leaders in Assam have been in "clandestine link" with the ruling BJP leaders and Chief Minister Himanta Biswa Sarma. A statement said that Trinamool Congress chairperson and West Bengal Chief Minister Mamata Banerjee envisions vast change for the furtherance and advancement of Assam, and its people with Trinamool Congress at the forefront. /IANS