Whenever any city of the first class located in any county having a population of more than twenty-one thousand (21,000) and an assessed taxable tangible valuation of not more than fifty million dollars ($50,000,000) shall by ordinance determine that it is essential for the protection of persons and property within such city to provide additional law enforcement services, the governing body of such city is hereby authorized to levy a tax of not to exceed one-half (1/2) mill upon all taxable tangible property within such city to pay the cost thereof and to pay a portion of the principal and interest on bonds issued by such city under the authority of Kan. Stat. Ann. § 12-1774, and amendments thereto. Before any tax is levied under the provisions of this section, the governing body shall by ordinance authorize the levy of such tax, stating the amount thereof and the purpose for which the levy is made. Such ordinance shall be published once each week for three (3) consecutive weeks in the official city newspaper and if within thirty (30) days next following the date of the last publication of such resolution, a petition signed by electors equal in number to not less than five percent (5%) of the qualified electors of the city, is filed with the county election officer, no levy shall be made under the provisions of this section without the question of levying the same having been submitted to and been approved by a majority of the electors of the city voting at an election called and held for such purpose. All such elections shall be noticed, called and held in the manner provided for the giving of notice, calling and holding of elections upon the question of the issuance of bonds under the general bond law.