TROY, Ohio -- Judicial officers from the United States District Court for the Southern District of Ohio conferred United States citizenship on 27 immigrants from 16 countries on Thursday.

The naturalization ceremony was held at Troy High School and civic leaders and several hundred high school students attended the ceremony, along with the immigrants and members of their families.

Immigrants are required to meet rigorous standards to become U.S. citizens. The standards are administered by the U.S. Citizenship and Immigration Services, which is an arm of the U.S. Department of Homeland Security.

The standards include a period of continuous residence in the U.S.; an ability to read, write and speak English; a knowledge and understanding of U.S. history and government and good moral character.