Honolulu, Jun 2 (IANS): More than 80 homes have been destroyed by the Kilauea volcano eruption in Hawaii in the four weeks since lava began flowing, a top official said.

The number of homes swallowed by the lava flowing from fissures has jumped to at least 87, up the from the 77 reported destroyed Thursday, Hawaii Civil Defence spokesman Talmadge Mango said Friday.

The report of mounting damage followed a mandatory evacuation order issued on Thursday night for a portion of the Leilani Estates subdivision in the midst of "vigorous lava eruptions" threatening homes, CNN quoted the Civil Defence Agency as saying.

Residents were advised to evacuate by Friday afternoon. Emergency responders have no plans to rescue anyone from the evacuated areas past the deadline.

"They are being asked to leave. Period," county spokeswoman Janet Snyder told reporters.

Four weeks have passed since the first eruption rocked Hawaii's Big Island and lava continues oozing from volcanic fissures.

The US Geological Survey (USGS) said the lava from the Kilauea volcano has covered an area of 5.5 square miles -- that's four times as big as New York's Central Park.

Fissure 8 remains the most active, the USGS said, sending "persistent fountains" of lava as high as 260 feet into the air.

Lava lobes from Fissure 8 were advancing 100 yards an hour, the USGS said.

"This is the hottest lava we've seen during this eruption," Wendy Stovall, a scientist with USGS told CNN. "Lava can't get hotter than where we are."

Besides the lava, there's also the danger of "vog", or volcanic smog.

In addition to volcanic particles that can cause eye, skin and respiratory irritation, residents were warned to be on the lookout for sharp, thin strands of volcanic glass fibres known as "Pele's hair", a reference to the Hawaiian goddess of fire.

The Civil Defence Agency warned it could cause injury if it got in residents' eyes or was breathed in.