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

The Turkish Disaster and Emergency Management Authority (AFAD) said Monday that a pre-dawn earthquake was felt in at least nine cities and was centered in the southeastern province of Kahramanmaras, about 20 miles from the major city of Gaziantep.

In Osmaniye, the city governor said 34 buildings had collapsed and at least five people had died.

Meanwhile, the governor's office in Urfa said 12 people were dead and 18 buildings had collapsed.

-ABC News' Engin Bas

The United States is “ramping up” assistance to Turkey and Syria, White House spokesperson John Kirby said Friday.

“In Turkey, a USAID Disaster Assistance and Response Team is already on the ground. And two of our most highly trained urban search and rescue teams are conducting operations in support of Turkish rescue efforts in Adana -- one of the hardest-hit areas inside the country,” Kirby said. “These teams have nearly 200 personnel combined between them, specialized equipment and canine support dogs, as well.”

Kirby said they’ve been able to “expand their operational reach with the support of U.S. military Blackhawk helicopters” to try and get around the extensive damage to roads and bridges.

“To date, they have been able to cover more than 630 sites across Adana [in Turkey],” Kirby said. “In Syria, our humanitarian partners continue to urgently scale up response efforts to reach people in need. That work will include, or has included, chartered flights that are transporting essential medical supplies and teams distributing hot meals and other food.”

The United Nations and its partners have successfully completed two humanitarian convoys into northwest Syria, Kirby said. One partner delivered 14 additional truckloads of supplies through the Bab-al-Hawa Crossing on the Turkey-Syria border, “totaling now 20 trucks of critical medicines, food and water to people in need over the last two days,” he said.

Kirby said U.S. sanctions imposed on Syria “will not prevent or inhibit prohibiting humanitarian assistance.”

-ABC News’ Justin Gomez