A looming government shutdown is threatening to close the gates to Fort Sumter, meaning the touchstone of the 150th anniversary of the first shots of the Civil War could be dark next week.

Even as lawmakers in Washington worked on Wednesday to avoid a federal shutdown, planners of Civil War sesquicentennial events wrestled with contingency plans for Tuesday's anniversary events.

"I'm shocked. This is a pivotal event in the nation's history," said Jeff Antley, who is coordinating arrangements for an estimated 1,000 re-enactors coming to the city. "You can't say we're going to reschedule for May. The money has been spent. The uniforms have been bought. The travel arrangements have been made."

Those re-enactors, some of them driving in from across the country and others flying in from abroad, are set to camp at Fort Moultrie on Sullivan's Island and Fort Sumter in Charleston Harbor beginning Friday night.

That's the same night that, if there is a shutdown, the forts would close. So-called nonessential government services, such as the National Park Service, would be affected first by any shutdown.

That leaves Antley trying to find other locations where hundreds of re-enactors can camp. And he may be making contingency plans that are never used.

Closing Sumter, where the war began on April 12, 1861, will mean no visitors to the fort during the milestone anniversary.

There are plans for a beam of light to shine skyward for several days, then split at 4:30 a.m. on Tuesday, the 150th anniversary of the first shots from Confederate land batteries at Union troops holding the fort.

Sumter will be bathed in blue light before the anniversary and then in red light Tuesday night to signify the burning fort. A shutdown would also cancel re-enactments of the Union surrender to Confederates set for next Thursday.

Years of planning have gone into the events. Sumter, as of Wednesday, is still making plans for the anniversary, said Linda Friar, a spokeswoman at the fort.

But despite planning, there will be no events on federal land if there is a shutdown, said David Barna, the chief spokesman for the National Park Service in Washington.

"We're hopeful there won't be a government shutdown. In the unfortunate event there is a shutdown, the entire national park system will close," he said. "We have big events going on nationwide. It's spring, but we have no flexibility."

Even with a shutdown, other 150th anniversary events in Charleston not on federal land, will be staged. They include re-enactments of the first shot fired from a mortar on James Island and the bombardment of Sumter by about 30 cannon ringing the harbor.

City spokeswoman Barbara Vaughn said concerts on Charleston's Battery -- one Monday night and another in the pre-dawn darkness on Tuesday entitled "When Jesus Wept" -- will also be held.

"I'm disappointed having to deal with this," Antley said. "I've got to feed 1,000 re-enactors. Those kinds of things are more important than having to deal with things like this where I have no ammunition to fix it with."