(Related video above: 40 people arrested in Lincoln Sunday night as protests continue)Sarpy County and the cities of Bellevue, Gretna, La Vista, Papillion and Springfield have each declared a state of emergency and established a curfew.The curfew is in effect from 8 p.m. Monday, June 1, to 6 a.m. Tuesday, June 2."The county and cities feel this action is necessary to reduce the vulnerability of people and the community to damage, injury, and loss of life and property resulting from civil disturbances connected to protests happening in Omaha," a press release stated. "This curfew restricts all non-essential travel and gatherings of the general public on public and private property, with the exception of those traveling to and from work, and any emergency services, including those seeking medical attention."The curfew will be revisited on Tuesday and a decision about extending it will be made at that time.