(USA TODAY) -- An American held captive for two years by an al-Qaeda-linked group in Syria was released Sunday, according to the Obama administration and his family.
"For two years, we have kept Peter Theo Curtis, a U.S. citizen held hostage in Syria, in our thoughts and prayers," White House national security adviser Susan Rice said in a statement. "Today, we join his family and loved ones in welcoming his freedom."
Curtis, 45, who is from Massachusetts, was held by the Jabhat al-Nusra, also known as the al-Nusra Front, a branch of al-Qaeda operating in Syria, Secretary of State John Kerry said in a statement.
Curtis is a published author and freelance journalist who writes under the name Theo Padnos, according to a statement released Sunday by his family expressing gratitude to the United States, Qatar and others who helped negotiate his release. He was captured shortly after he crossed into Syria in October 2012.
"My heart is full at the extraordinary, dedicated, incredible people, too many to name individually, who have become my friends and have tirelessly helped us over these many months," Nancy Curtis, his mother, from Cambridge, Mass., said in the statement. "Please know that we will be eternally grateful."
Nancy Curtis said the family did not know the details surrounding the negotiation for Curtis' release but said they "were repeatedly told by representatives of the Qatari government that they were mediating for Theo's release on a humanitarian basis without the payment of money."
Curtis was handed over to United Nations peacekeepers in Golan Heights on Sunday evening, according to a U.N. statement. After receiving medical attention, he was handed over to U.S. government representatives, the statement said.
Footage of Curtis, in a video obtained by Al-Jazeera and The New York Times in late June, showed the American looking disheveled. Speaking from a script, Curtis stated his name and said he was a journalist from Boston, Al-Jazeera reported. He said his captors treated him well, and he "had everything" he needed, the Times reported.
"Over these last two years, the United States reached out to more than two dozen countries, asking for urgent help from anyone who might have tools, influence or leverage to help secure Theo's release and the release of any Americans held hostage in Syria," Kerry said.
Rice said Curtis will be reunited with his family shortly.
"We will continue to work tirelessly on behalf of all Americans who are held overseas so that they can be reunited with their families as well," Rice said.
Curtis' release comes days after the Islamic State released a video showing the beheading of James Foley, 40, a U.S. freelance reporter.
Steven Joel Sotloff, a photojournalist and former University of Central Florida student, remains a hostage of the terrorist group and was threatened with death in the same video that portrayed Foley's killing.
Nancy Curtis said in a statement that she had gotten to know the Foley family and appealed to the captors of remaining hostages to release them.
"My entire focus right now is on helping the other families of those still being held in Syria and on taking care of my son," she said.