"I am deeply saddened by the loss of life and devastation caused by the earthquake in Turkey and Syria. I have directed my team to continue to closely monitor the situation in coordination with Turkey and provide any and all needed assistance," the president tweeted from his official account.
"Our teams are deploying quickly to begin to support Turkish search and rescue efforts and address the needs of those injured and displaced by the earthquake," he added in a statement later released by the White House.
The magnitude 7.8 quake, which hit before sunrise in bitter winter weather, was the worst to strike Turkey this century. It was followed in the early afternoon by another large quake of magnitude 7.7.
Turkish government officials said at least 1,651 people had died in the 7.8-magnitude tremor, with another 968 confirmed fatalities in neighboring Syria, putting the total at 2,619.
It was not immediately clear how much damage had been done by the second quake, which like the first was felt across the region and endangered rescuers struggling to pull casualties from the rubble.
"We were shaken like a cradle. There were nine of us at home. Two sons of mine are still in the rubble, I'm waiting for them," said a woman with a broken arm and injuries to her face, speaking in an ambulance near the wreckage of a seven-story block where she had lived in Diyarbakir in southeast Turkey.
In Diyarbakir, Reuters journalists saw dozens of rescue workers searching through a mound of debris, all that was left of a big building, and hauling off bits of wreckage as they looked for survivors. Occasionally they raised their hands and called for quiet, listening for sounds of life.
The White House statement said Biden had called on US officials to reach out to their Turkish counterparts to coordinate on assistance, and that humanitarian groups supported by the United States were responding to the destruction in Syria.
"Today, our hearts and our deepest condolences are with all those who have lost precious loved ones, those who are injured, and those who saw their homes and businesses destroyed," he said in the statement.
President Tayyip Erdogan, who is preparing for a tough election in May, called it a historic disaster and the worst earthquake to hit Turkey since 1939, but said authorities were doing all they could.
"Everyone is putting their heart and soul into efforts although the winter season, cold weather and the earthquake happening during the night makes things more difficult," he said.
This report was prepared using Reuters and Agence France-Presse.