"I hereby tender my resignation from the office of the Speaker, Odisha Legislative Assembly with effect from today," Mr Pujari said in a letter submitted to Deputy Speaker Sananda Marndi.
Asked the reason for his sudden resignation, Mr Pujari told newsmen, "I have decided to spend more time with the people of my constituency and therefore resigned from the post of speaker."
He declined to comment on whether he took the decision due to pressure from anyone.
Mr Marndi said he has received Mr Pujari's resignation but refused to say anything on the reason behind it.
It is understood that Mr Pujari is likely to be inducted in the council of ministers in the proposed reshuffle of the ministry expected in the next couple of days.
Sources said the Parliamentary Affairs department has already informed the Raj Bhavan for the swearing-in ceremony.
"You will know it (ministry reshuffle) very soon. Be patient and wait," Mr Patnaik told reporters earlier in the day while replying to a question whether the ministry expansion would take place before his Delhi visit scheduled on May 7.
Mr Patnaik will leave for Delhi on Sunday to attend the meeting of chief ministers of Naxal-affected states on Monday.
Meanwhile, Odisha Governor S C Jamir, who is on a visit to his home state Nagaland, is scheduled to return to here tomorrow morning.
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