The hostages are now free and in neighboring Oman, according to the White House. They were flown to Muscat with an Omani government plane and were met by U.S. consular staff, officials said.
A third American who was believed held by the Houthis was not released, and it's unclear exactly who has him, a senior administration official told CNN on Sunday.
Houthi rebels also released other hostages, including one Briton, a U.K official told CNN, and three Saudi nationals, according to Oman state TV.
Earlier Sunday, a diplomat in the Yemeni capital of Sanaa said six foreign hostages -- three Americans, two Saudis and one Briton -- would be flown to Oman.
Oman TV showed some hostages getting off the plane in Muscat and being greeted by a diplomat.
One of the freed Americans was identified as Scott Darden
, a 45-year-old employee of the New Orleans-based company Transoceanic Development, who was taken hostage by Houthi rebels in Sanaa in March, the U.S. administration official said. The official identified the other released hostage as Sam Farran.
The two men had been trying to flee Yemen when they were taken and held.
"When the uprising happened, Scott called Sam, who he knew, for help in getting out of Yemen. They were captured together before they could leave the country," said Transoceanic Development spokesman Ken Luce.
"I just received a phone call from my husband who sounds elated and overjoyed to be in Oman," Darden's wife Diana Loesch told CNN before heading to Muscat to meet him.
Kerry thanks Omani government
The hostage release was negotiated by the Omanis, the U.S. administration official said, and comes at a time of intensified diplomacy to try to end a war that has been raging for over six months and left nearly 5,000 people dead -- including 2,000 civilians, according the United Nations and to rights groups.
U.S. Secretary of State John Kerry thanked the Omani government Sunday, adding that the U.S. government welcomed the hostages' release and would keep pushing for the release of other detained Americans.
"We will continue to work tirelessly to pursue the release of all Americans detained abroad unjustly, including those who remain in the region," Kerry said in a statement.
Release ahead of possible talks
Shia Houthi rebels backed by Iran seized the presidential palace in Yemen's capital in January, which forced Saudi-backed President Abdu Rabu Mansour Hadi to flee into exile to Saudi Arabia.
The U.S. government, along with other Western nations, pulled embassy staff out of Sanaa in February. They were followed by the remaining U.S. special operations forces, who left in March.
That same month, a Saudi-led coalition launched airstrikes against Houthi rebels and in April the U.N. Security Council demanded that Houthis withdraw
from the areas they've seized.
Upcoming U.N.-sponsored talks
are supposed to focus on finding a strategy for implementing the resolution, senior Houthi officials told CNN.
But earlier this month, President Hadi's office said he wouldn't agree to attend talks with Houthi rebels
unless they comply with the resolution first and withdraw from the capital.