A collapsed building is seen following an earthquake in Pazarcik, in Kahramanmaras province, southern Turkey, early Monday. Depo Photos via AP

ANKARA, Turkey — A powerful 7.8 magnitude earthquake hit southeast Turkey and Syria early Monday, toppling buildings and sending panicked residents pouring outside in a cold winter night. At least 100 were killed, and the toll was expected to rise.

Rescue workers and residents frantically searched for survivors under the rubble of crushed buildings in multiple cities on both sides of the border. In one quake-struck Turkish city, dozens pulled away chunks of concrete and twisted metal. People on the street shouted up to others inside a partially toppled apartment building, leaning dangerously.

The quake, felt as far away as Cairo, was centered north of the city of Gaziantep in an area about 60 miles from the Syrian border.

On the Syrian side of the border, the quake smashed opposition-held regions that are packed with some 4 million Syrians displaced from other parts of the country by the long civil war. Many of them live in decrepit conditions with little health care. At least 11 were killed in one town, Atmeh, and many more were buried in the rubble, a doctor in the town, Muheeb Qaddour, told The Associated Press by telephone.

“We fear that the deaths are in the hundreds,” Qaddour said, referring to the rebel-held northwest. “We are under extreme pressure.”

On the Turkish side, the area has several large cities and is home to millions of Syrian refugees.

Turkish President Recep Tayyip Erdogan said on Twitter that “search and rescue teams were immediately dispatched” to the areas hit by the quake.

“We hope that we will get through this disaster together as soon as possible and with the least damage,” he wrote.

People try to reach trapped residents in a collapsed building in Diyarbakir, southeastern Turkey, early Monday. Mahmut Bozarsan/Associated Press

There were at least 6 aftershocks, and Interior Minister Suleyman Soylu urged people not to enter damaged buildings due to the risks.

“Our priority is to bring out people trapped under ruined buildings and to transfer them to hospitals,” he said.

Tallies from various officials put the toll at at least 38 dead in Turkey and 62 in Syria.

At least 130 buildings tumbled down in Turkey’s Malatya province, neighboring the epicenter, Gov. Hulusi Sahin said. In the Turkish city of Diyarbakir, at least 15 buildings collapsed. Rescue teams called for silence as they listed for survivors in a toppled 11-story building.

In northwest Syria, the opposition’s Syrian Civil Defense described the situation in the rebel-held region as “disastrous” adding that entire buildings have collapsed and people are trapped under the rubble. The civil defense urged people to evacuate buildings to gather in open areas. Emergency rooms were full of injured, said Amjad Rass, president of the Syrian American Medical Society.

The U.S. Geological Survey said the quake was centered about 20 miles from Gaziantep, a major city and provincial capital. It was centered 11 miles deep, and a strong 6.7 aftershock rumbled about 10 minutes later.

Syria’s state media reported that some buildings collapsed in the northern city of Aleppo and the central city of Hama.

In Damascus, buildings shook and many people went down to the streets in fear.

The quake jolted residents in Lebanon from beds, shaking buildings for about 40 seconds. Many residents of Beirut left their homes and took to the streets or drove in their cars away from buildings.

The earthquake came as the Middle East is experiencing a snowstorm that is expected to continue until Thursday.

Turkey sits on top of major fault lines and is frequently shaken by earthquakes.

Some 18,000 were killed in powerful earthquakes that hit northwest Turkey in 1999.