WASHINGTON — The White House is weighing an urgent response to help trapped religious minorities in Iraq, with one option being delivery of humanitarian aid, according to two people familiar with administration discussions.

President Barack Obama huddled with his national security team Thursday morning to discuss the crisis stemming from a Sunni extremist group's gains in Iraq's north. Furthering their gains, the militants seized Iraq's largest dam Thursday, placing them in control of enormous power and water resources and access to the river that runs through the heart of Baghdad.

While the White House did not publicly outline the range of options under consideration, officials said the U.S. strongly condemns the extremists' assault on minorities, including the Yazidis, who follow an ancient religion with ties to Zoroastrianism, and Christians.

"The situation is nearing a humanitarian catastrophe," White House spokesman Josh Earnest said. "We are gravely concerned for their health and safety."

Among the most pressing concerns is the plight of the Yazidis, who fled the Kurdish town of Sinjar in recent days. Thousands fled their homes for the mountains after the Islamic State group issued an ultimatum to convert to Islam, pay a religious fine, flee their homes or face death.

If Obama were to approve humanitarian assistance to the Yazidis and others, it could be delivered via air drops by the U.S. military. The military could also advise and assist the Iraqi air force on where and how to deliver humanitarian relief supplies.

The people familiar with the administration's thinking insisted on anonymity because they were not authorized to discuss the matter by name.