ANNAPOLIS, Md. (AP) — A Maryland judge has allowed a referendum on the state's congressional redistricting map to continue after a challenge by the Maryland Democratic Party, but an appeal is planned.

Maryland's Democratic Party filed a complaint against the Maryland State Board of Elections in July, saying the board had improperly accepted some petition signatures that put the map issue on the November ballot.

The board accepted a total of 59,201 signatures submitted by map opponents, more than the required 55,736. But the Maryland Democratic Party challenged more than 5,000 of the signatures.

Opponents say the redrawn map approved in 2011 has been gerrymandered to favor Democrats. Democrats say it reflects demographic changes.

The Democratic Party has appealed Friday's ruling to the state's highest court and expects the case to be heard Thursday.