Six people, including at least two doctors, were detained by federal authorities Tuesday afternoon while blocking an entrance to the United States Border Patrol’s San Diego Sector headquarters in Chula Vista.

A larger group, which includes Doctors for Camp Closure, Families Belong Together and Never Again Action, has been asking U.S. Customs and Border Protection to allow licensed medical doctors to vaccinate detained migrant children for the flu after three children died from the disease in custody last year.