Fort Richardson officials announced Monday that they have closed a section of the post for recreational use following a weekend encounter in which a wolf grabbed a dog by the nape of its neck, then trailed two joggers and their dogs after releasing its catch unharmed.

The encounter, the first serious confrontation between wolf and dog reported in the area since last winter, prompted Army officials to indefinitely close the fort north of Artillery Road in Eagle River.

The encounter took place Sunday afternoon, when two people were jogging with three dogs on Artillery Road about a half mile west of its intersection with Route Bravo. One of the dogs, described as a pointer-retriever mix, fell behind the group, said Bruce Bartley, spokesman for the Alaska Department of Fish and Game.

"The older dog kind of lagged behind, and they heard a yelp, and turned around and looked and a wolf had grabbed it," Bartley said. "So the people turned around and ran at the wolf, and he promptly drops the dog."

The gray-coated wolf, however, wasn't scared off. It followed at a distance for about a half mile while one person hung back to scare it and the other led the dogs away, said Rick Sinnott, Anchorage-area wildlife biologist with Fish and Game. The dog was uninjured in the encounter.

Fort and wildlife officials would not name the joggers Monday. Bartley described them as experienced trail users who were taken off-guard by the unseasonable attack. Wolf encounters typically occur in the midst of winter, when they are having trouble finding food and can be prone to snatching pets, he said.

The joggers had not signed in as required for their trip on base and also apparently did not have their dogs on leashes, in violation of base policy, Army spokesman Bob Hall said.

"There can be some severe consequences," Hall said of failing to sign in. "The commander can just determine to bar them from recreating on the installation for a year."

He said he didn't know what specific action, if any, was being taken against the joggers.

The encounter marked the first serious confrontation reported since a series of wolf attacks on Fort Richardson and along Knik Arm left three dogs dead and several others wounded in late 2007, Sinnott said. Those encounters, which included wolves stalking people and pets, prompted Army officials to close the area north of Artillery Road for about a month.

State wildlife biologists say there are four or five wolf packs in and around the municipality and they are known to occasionally take pets from yards. Only one pack, however, is thought to be responsible for the series of attacks then and is suspected in the recent encounter. That is the Elmendorf pack, which is so named because it frequents the Air Force base and Fort Richardson.

The 2007 attacks stopped after a young female from the pack was shot in December that year. There have been a few close encounters involving pets and wildlife since, including with coyotes this spring, but no serious wolf confrontations, Sinnott said.

"It's isolated in the sense of being the first one really in the last year or so, but it's not isolated in the sense that this pack has done it before, so that's kind of factoring into our concern," Sinnott said. "In this case, it is very likely that it's a wolf that has done this before."

In addition to closing the area, Army officials planned to dispatch military police to conduct patrols in the area to watch for aggressive animals, Hall said.

Sinnott said officials have no immediate plans to hunt the wolf down. The animal appeared to be alone and there was no indication it was protecting a nearby den -- the confrontation seemed predatory, he said.

"We're always looking for a pattern, so if it happens again we'll have to do something," Sinnott said. "It's one thing if it's happening in the winter when the wolves are in packs and they're hungry, but if it's just a single wolf that's decided to start picking off dogs like that, that wouldn't be a good thing."