In a statement, the Thiruvananthapuram MP said: "I regret that some preferred the unseemly public airing of internal differences, thereby creating a needless controversy in a matter in which AICC's view was binding. I hope wisdom will prevail in future."
Justifying his openness to attend the seminar, Tharoor said the topic for the seminar "does not involve any matter of sensitivity in Kerala but was on 'Centre-state relations', where there is no real difference of opinion between our parties".
He said he respects the views of the party President and has conveyed the organisers his inability to participate.
Tharoor also highlighted that a month ago, a similar invitation was extended for a seminar on the sidelines of the CPI-M state party conference. "On that occasion also, I consulted the AICC President and a suitable decision was taken without any media controversy," he said.
Gandhi on Monday asked the senior party leader to refrain from attending the CPI-M seminar to be held in April, directing him to listen to the Kerala leadership.
The development came after he joined a meeting of Congress "rebels", apparently ditching the Congress's Kerala unit by planning to attend the Left's seminar.
As per sources, Congress leaders from Kerala met Gandhi at the party's parliamentary office in Delhi to intimate her of the "embarrassing" development.