By Jon Herskovitz and Lawrence Hurley

AUSTIN, Texas/ WASHINGTON (Reuters) - A Texas law requiring voters to show a government-issued form of photo identification before casting a ballot is discriminatory and violates the U.S. Voting Rights Act, a U.S. appeals court ruled on Wednesday.

The U.S. Court of Appeals for the Fifth Circuit, in a close decision among a special 15-judge panel, also sent the case back to a district court to examine claims by the plaintiffs that the law had a discriminatory purpose.

The New Orleans-based Fifth Circuit, which has a reputation as one of the most conservative federal appeals courts, asked the district court for a short-term fix to be used in Texas in the November general election.

U.S. Attorney General Loretta Lynch applauded the ruling and said in a statement, "This decision affirms our position that Texas’s highly restrictive voter ID law abridges the right to vote on account of race or color and orders appropriate relief before yet another election passes."

Critics of the law said it and similar statutes that have been passed in Republican-governed states were intended to make it harder for minorities such as African-Americans and Hispanics, who tend to support Democrats, to vote. Backers of these laws have said they are necessary to prevent voter fraud.

The court ruled 9-6 that the Texas law had a discriminatory effect. The judges were divided differently on other parts of the ruling.

"We acknowledge the charged nature of accusations of racism, particularly against a legislative body, but we must also face the sad truth that racism continues to exist in our modern American society despite years of laws designed to eradicate it," the court said.

Challengers of the Texas law have said that up to 600,000 people would be unable to vote if the law was fully in effect.

The law passed in Republican-dominated Texas was one of the strictest voter ID laws in the United States.

A federal judge in Wisconsin on Tuesday softened that state’s law, saying people without a photo ID should be able to vote in November if they agree to sign an affidavit explaining why they could not obtain identification.

A federal appeals court is expected to rule soon on a similar law in North Carolina. A district court judge upheld the measure in April.

"Preventing voter fraud is essential to accurately reflecting the will of Texas voters during elections, and it is unfortunate that this common-sense law, providing protections against fraud, was not upheld in its entirety," Texas Attorney General Ken Paxton, a Republican, said in a statement.

(Reporting by Jon Herskovitz in Austin, Texas, and Lawrence Hurley in Washington, D.C.; Editing by Leslie Adler, Toni Reinhold)