Trinamool Congress' (TMC) Rajya Sabha MP Sushmita Dev on Wednesday resigned from the Upper House, two days after fellow lawmaker Sukhendu Sekhar Ray quit, further reducing the party's strength in Parliament, where TMC also faces a rebellion among its Lok Sabha lawmakers.Trinamool Congress (TMC) leader Sushmita Dev on Wednesday resigned as a member of the Rajya Sabha (PTI)"I do hereby resign from the membership of Rajya Sabha, which may please be accepted with immediate effect," Dev wrote in the letter addressed to Rajya Sabha chairman CP Radhakrishnan.Ray and Dev's resignation will pave the way for by-elections in the Upper House. The BJP, which has 208 seats in the assembly, is set to win both seats. According to the law, each by-election will be held independently.The twin resignations deepen the crisis in the TMC, which played a key role in defeating the Constitution amendment bill to implement early Delimitation.Dev, daughter of Congress stalwart late Santosh Mohan Dev had joined TMC from the Congress amid the Bengal-based party's plan to expand in the national politics. She has been a Rajya Sabha member for two terms. Dev, who won her second term in 2024, had four more years in the Upper House.Meanwhile, former chief whip of TMC in Lok Sabha, Kakoli Ghosh Dastidar has claimed that 20 MPs have written to Lok Sabha Speaker Om Birla to consider as a separate bloc and not part of the TMC. Dastidar is expected to meet Birla on Wednesday.