Monday’s earthquake has killed at least 912 people in several Turkish provinces and injured 5,382 others, Turkish President Recep Tayyip Erdogan announced during a press conference.

Thousands of buildings were destroyed, Erdogan said.

Turkey’s disaster and emergency management agency, AFAD, is deploying 1,898 search and rescue workers along with 150 vehicles in response to the deadly earthquake. Turkey’s national police force has deployed 130 tactical unit members with mobile command centers and kitchens to the city of Kahramanmaras, near the quake’s epicenter. A total of 300,000 blankets were also sent to the region, which is deep in winter weather.

Meanwhile, at least 239 people were killed and some 600 were injured in government-held areas of Syria, according to Syrian state media. In rebel-controlled areas, at least 147 people were killed, according to the Syrian civil defense and medical group that operates in opposition-held areas, known as the White Helmets.

The Syrian Observatory for Human Rights, a United Kingdom-based monitoring group, put the overall death toll at 320.

The United States "is profoundly concerned" by the reports of the "destructive earthquake" in Turkey and Syria, and "will continue to closely monitor the situation," U.S. national security adviser Jake Sullivan said in a statement late Sunday night.

"We stand ready to provide any and all needed assistance," Sullivan added, noting that U.S. President Joe Biden "has directed USAID and other federal government partners to assess U.S. response options to help those most affected."

The U.S. Geological Survey measured the quake in Turkey at magnitude of 7.8.

-ABC News' Lauren Minore

Turkey's Disaster and Emergency Management Authority (AFAD) said Monday's earthquake has killed at least 76 people in seven cities.

Meanwhile, at least 99 were killed in three Syrian cities, according to Syria's Ministry of Health.

The 7.4-magnitude quake struck the the town of Pazarcik in Turkey's southeastern Kahramanmaras province at 4:17 a.m. local time and was followed by at least 17 aftershocks, the strongest measuring 6.6.

The quake was felt intensely in several surrounding provinces, prompting AFAD to declare a "level 4 alarm," which calls for international assistance.

-ABC News' Will Gretsky

Syria's Ministry of Health said Monday that at least 42 people were killed in the northwestern cities of Aleppo, Hama and Lattakia, following a pre-dawn earthquake in neighboring Turkey.

The Syrian civil defense and medical group that operates in opposition-held areas, known as the White Helmets, has declared a state of emergency in the country's northwest

People are "trapped under the rubble," the White Helmets said, adding that it "calls on residents to evacuate residential buildings, go to open places far from buildings, and inform our teams about those trapped under the rubble."

-ABC News' Will Gretsky