BRUSSELS—The International Federation of Football Associations (FIFA) won't strip Qatar of the 2022 World Cup over reported violations of migrant workers rights, but it will scrutinize the country's promised improvements in treatment of workers building infrastructure for the tournament, a senior official said Thursday.

At a largely symbolic hearing at the European Parliament on the treatment of thousands of foreign workers building Qatar's infrastructure ahead of the high-profile football event, Theo Zwanziger, a member of...