A group representing African-American pastors is criticizing new rules that limit early voting in Ohio, saying that the changes will dampen black turnout.

The voting rules would affect several counties in the state, including those with big cities that lean Democratic, such as Cleveland, Akron, Columbus and Toledo. Under the rules, people can only cast votes between 8 a.m. and 5 p.m. -- hours when many people are working. The laws also cut down the number of weekends in which people Those cities also boast substantial African-American populations.

"There are politicians doing the unthinkable: they are making it harder for their constituents to exercise our constitutionally guaranteed right to vote," said Rev. Tony Minor of the African American Ministers Leadership Council, in a statement. "And once again, these suppression efforts are aimed directly at African Americans in swing states.”

“We have strengthened our efforts to educate our congregations and our communities about their rights and their civic responsibilities," he added.

Many black churches in states that allow early voting hold organized trips to polling places after Sunday church services. Florida, another hotly contested swing state, has imposed similar rules limiting Sunday voting.

A studyfrom a group called Northeast Ohio Voter Advocates found that African Americans were disproportionately represented among early voters in the state. (While African Americans of voting age made made up only 28 percent of the population of Cuyahoga County, where Cleveland is located, 56 percent of early voters there were black.)

But several traditionally Republican counties in Ohio have extended their hours. In addition, the new early voting rules also did not affect military voters, who also tend to vote for Republicans.

Voting rights groups have called on the state to make the voting rules uniform.

“Voters have a responsibility to empower themselves,” said Mike Brickner of the ACLU in a statement. “But elections officials also have a responsibility to help them by instituting fair and consistent rules.”

The fight over Ohio's early-voting rules came to national attention after the Obama campaign and Ohio Democrats filed a lawsuit calling the new rules unconstitutional, and pushed for restoring early-voting rights for everyone in the state. Mitt Romney, the Republican presidential nominee, falsely claimed that the lawsuit was meant to keep people in the military from voting early.

A study released by the Urban League in July found that President Obama would have a difficult time winning the Buckeye State if black turnout dipped from its record height of 96 percent in 2008 back down to 2004 levels.

President Obama is currently leading Mitt Romney in most polls for the state.

Ohio is famously a bellwether for the nation’s electoral outcome. The Buckeye State has correctly predicted the eventual president in every election since 1944, except for 1960.