ISLAMABAD (Reuters) - Pakistan's election commission on Monday ruled that a party aligned with candidates backed by former premier Imran Khan is not eligible for extra reserved seats in the legislature, another blow to the embattled group's governing prospects.

The decision represents another setback to Khan, who is in jail following a string of convictions, despite his candidates winning the most seats overall in the Feb. 8 vote.

(Reporting by Asif Shahzad, Charlotte Greenfield; Editing by YP Rajesh and Toby Chopra)