JAKARTA, Indonesia (CNN) — Relief and rescue crews and medical teams on Saturday raced to help the victims of the strong earthquake that rocked the Indonesian city of Yogyakarta and adjacent areas along the southern coast of Indonesia’s Java island.

The 6.2 magnitude quake that struck just before 6 a.m. (7 p.m. ET, 11 p.m. GMT Friday) shook and rippled through a heavily populated region, killing at least 271 people, injuring hundreds, and leveling and damaging many structures. (Updata: Reuters now says, “Indonesia quake toll exceeds 1,000 – official“)
There are fears that many people are trapped in the rubble of collapsed buildings.

The epicenter was 25 kilometers (16 miles) southwest of the city and near the erupting volcano Mount Merapi. Scientists believe the quake could affect volcanic activity.

The quake was felt across central and eastern Java, with aftershocks reported.

The city of Yogyakarta — a popular tourist destination and a historic royal metropolis that sits near the Indian Ocean — appeared to endure the brunt of the damage.

“People here reported that this was the largest earthquake they had ever felt in their lives in this area,” Brook Weisman-Ross, disaster coordinator for Plan International, told CNN from Yogyakarta.

Hospitals overwhelmed

Health care providers and hospitals have been overwhelmed, and the casualty figures are expected to rise. More injured people were pouring into Yogyakarta’s main hospital, many of them in buses and trucks, a hospital spokesman said.

Many people — fearing aftershocks, a tsunami and more structural damage — have left their dwellings and have raced to higher ground. But an Indonesian meteorologist said the shallow quake did not cause a tsunami.

Search-and-rescue teams in Yogyakarta said they saw extensive damage to buildings and homes and that some communications were down.

Weisman-Ross said he was “shaken rather violently from my bed with furniture flying and chunks of concrete falling from the walls of my hotel room.”

Outside, Weisman-Ross said he saw large cracks in the walls of the hotel and other buildings in the area. As he rushed across town to check on his staff, he saw small, older buildings with collapsed roofs or walls.

Government officials said plans are in place to bring in relief supplies and rescue teams, and non-governmental organizations have geared up to provide help. Citizens in the region need medicine, tents and blankets.

Latifur Rahman is the disaster management coordinator of International Federation of the Red Cross and Red Crescent Societies. Speaking from Jakarta, he confirmed reports of flattened and damaged structures, including a collapsed local hospital. He said medical teams are mobilizing and preparing to set up a field hospital in the region.

Relief flights had to be diverted from Yogyakarta because of damage to that city’s airport runway.

Because of fears over the volcano, evacuation centers and emergency personnel are in place.

Personnel deployed to respond to the volcano can conceivably be used to help out with search, rescue and relief in the aftermath of the earthquake.