Anxious or ambivalent, residents in Maine, New Hampshire and Massachusetts will learn today whether the Portsmouth Naval Shipyard and Brunswick Naval Air Station will be targeted during the first round of military base closings in a decade.

Defense Secretary Donald Rumsfeld is set to make public this morning which of the nation’s 425 military installations he wants to close or realign.

In Brunswick, Maine, the leader of an effort to save the Navy air base said the mood has been ambivalent and he fears residents were too confident of a positive outcome. Base supporters will be watching the announcement on a big-screen television.

On the Maine-New Hampshire border, residents who recall the Portsmouth Naval Shipyard narrowly escaping closure in 1993 were more guarded.

“I’m apprehensive as hell because I’ve seen too many indicators that I interpret to reflect moving toward a closure recommendation,” said William McDonough, a former shipyard commander who leads a community group lobbying on Portsmouth’s behalf.

Portsmouth’s supporters planned no public observances today, but supporters were ready to spring to action if the base is targeted, he said.

Both bases serve as important economic engines. Brunswick has 4,800 military and civilian employees, and Portsmouth has 4,300 civilian workers drawn from Maine, New Hampshire and Massachusetts. Together, the two bases pump more than $300 million into the regional economy.

Rumsfeld’s recommendations will be submitted to an independent Base Realignment and Closure Commission that will hold hearings and make a final recommendation to President Bush by Sept. 8.

The shipyard, one of four public yards and the nation’s oldest, narrowly escaped closing more than a decade ago, thanks to the efforts of Maine’s and New Hampshire’s congressional delegations. South Carolina’s Charleston Naval Shipyard was closed instead.

Supporters contend the base, on an island in the Piscataqua River between Maine and New Hampshire, has the most experience in overhauling and refueling nuclear submarines.

McDonough said that if the Pentagon properly researched the shipyard’s capabilities there is no doubt it would remain open. But he said he fears that those findings will be overlooked by Pentagon officials eager to slash costs.

“I just have a pretty sad feeling that it has been predetermined,” said McDonough, who lives in Kittery, Maine. “The word is that they’re going to have to sacrifice another base. I think that’s a horrible, outrageous mistake.”

In contrast, many supporters felt relatively secure about the future of the Brunswick Naval Air Station, 75 miles up the coast from Kittery.

Even though it is host to P-3 Orion surveillance aircraft, which are designed to hunt Russian submarines, the base has undergone more than $100 million in upgrades and its location makes it closest to European shipping lanes. It also has room to expand.

But many of the same arguments applied to Maine’s Loring Air Force Base, which played a key role in refueling military aircraft headed to the Middle East for the first Gulf War. None of that kept the base near the Canadian border from closing.

“When the Gulf War ended, no one ever thought that six months later they would be listed for closure,” said Brian Hamel, who was appointed by then-Maine Gov. John McKernan to lead an agency charged with redeveloping the base.

One thing working in Brunswick’s favor is four previous rounds of base closings have left it as the only active duty military airfield in New England.

But Rick Tetrev, chairman of the Brunswick Naval Air Station Task Force, said he was preparing for the worst, while hoping that he and other base supporters would receive some good news when they watch the release of the list on television this morning at the Atrium Hotel in Brunswick.

“We’re anxious to hear the word and get on with business, whatever it is,” he said.

Hamel, now a consultant on base closing issues, said he understands what communities surrounding the bases are going through.

“The community is on pins and needles. The base is … a huge part of the community, economically and culturally,” Hamel said Thursday. “There’s not a community out there that wants to see the base closed.”