PORTLAND — Backers of a citizen petition drive to legalize marijuana for recreational use in Maine will file a lawsuit in Kennebec County Superior Court on Thursday that challenges the Secretary of State’s decision to disqualify the measure from the November ballot.

Campaign leader David Boyer and attorney Scott Anderson will announce the details of the suit at a news conference Thursday at 1 p.m. in the office of Portland law firm Verrill Dana.

Anderson is representing a group of Maine voters who signed the petition in support of the initiative.

Last week, the Maine Secretary of State’s Office announced that a proposed initiative to end marijuana prohibition in Maine did not qualify for the November ballot. Of the 61,123 signatures of registered Maine voters required, state officials determined that initiative backers submitted 51,543 valid signatures.

More than 17,000 valid signatures were not included in the count because the signature of an individual notary Stavros Mendros did not match his signature the state has on file.