Four residents and a group of atheists have filed a lawsuit over a cross depicted in the seal and flag of a county in Pennsylvania, U.S.A.

The lawsuit was filed on Aug. 16 before the U.S. District Court of Eastern Pennsylvania against Lehigh County, claiming that the cross violated the Establishment Clause.

In March last year, Lehigh County commissioners unanimously voted to oppose the removal of the cross from the seal and flag after the Freedom From Religion Foundation (FFRF) sent a letter.

"It is the position of Lehigh County that the presence of the cross on the seal among all the other items of historical significance has the secular purpose of recognizing the history of the county," the letter stated, according to Lehigh Valley Live.

FFRF is the plaintiff in the lawsuit along with Lehigh residents Stephen Meholic, David Simpson, John Berry and Candace Winkler

They are asking the court to rule that the cross on the seal and flag violate the U.S. Constitution and issue a permanent injunction against the county.

"It is well settled law that government entities may not include religious images on their official seals," said the foundation's staff attorney, Patrick Elliott, via email. "Lehigh County is a pluralistic community that includes persons of minority faiths and of no religion. We look forward to the county redesigning the seal to come into compliance with the First Amendment."

FFRF sent letters to the county in November 2014 and January last year about the cross.

The Board of Commissioners, in its reply, told FRFF that "the cross, one of more than a dozen elements, was included to honor the original settlers of Lehigh County, who were Christian."

In 1944, the board adopted the imagery that appears on the seal.

The plaintiffs said that "Lehigh County had a religious purpose, rather than a secular purpose, in adopting a seal and flag that prominently feature a Latin cross."

They said the cross "has the primary effect of both advancing religion and expressing Defendant's preference for Christianity above all other religions and nonreligion."