National Guard troops arrived in a Hawaii town threatened by a slow-moving river of molten lava on Thursday, and were greeted with cheers by residents of the Big Island community where they are to provide security as the volcanic flow advances.

The lava flow from the Kilauea volcano has been slithering toward the Big Island village of Pahoa for weeks, although it slowed to a turtle's pace on Thursday and at last watch had advanced only a few feet (meters) over several hours, said Darryl Oliveira, director of Hawaii County Civil Defense.

"The activity on the flow front is very inactive, very sluggish," Oliveira told reporters.

The lava threatens to destroy homes and cut off a road and a highway through Pahoa, but officials have not offered any predictions on when exactly it could bisect the town of about 800 residents at the site of an old sugar plantation.

No homes have been destroyed so far, and a finger of lava that threatens one house on the edge of town has not crept closer to it since Wednesday night, Oliveira said.

Some 83 National Guard troops arrived on Thursday in the community, where some residents have expressed concern about potential looters targeting evacuated homes. The troops, who are at checkpoints in town, were cheered by residents who waved and walked up to start conversations.

"These are local troops, people from the community. They'll be here working to take care of their family and friends," Oliveira said.

The glowing leading edge of the lava flow, which can reach temperatures of about 2,100 degrees Fahrenheit (1,149 degrees Celsius), is about 155 yards (meters) from Pahoa Village Road, the main street through town, officials said.

Residents of about 50 dwellings in what civil defense officials called a "corridor of risk" have been asked to be ready to leave. At this stage, 10 to 15 homes lie in the direct path of the lava's leading edge, which measures about 60 yards (meters) across, officials said.

In another challenge, authorities say the lava could take down power poles and leave residents without electricity, and one pole was already surrounded by lava but still stands, a spokeswoman for the local utility said.

Kilauea has erupted continuously from its Pu'u O'o vent since 1983, with its latest lava flow beginning on June 27. The last home destroyed by lava on the Big Island was at the Royal Gardens subdivision in Kalapana in 2012.