The kidnappers had been seeking a ransom, but a Bedouin source said the authorities had agreed to free four fellow tribesmen from police custody in exchange for the two tourists, according to Reuters.
The Americans, both women, were aboard a bus with three other holiday-makers when it was held up by gunmen between Mount Sinai and Sharm el-Sheikh. Their Egyptian guide was also taken, the Associated Press reported. They were released hours later.
Bedouins abducted a group of Chinese workers in northern Sinai earlier this week, and also demanded the release of fellow tribesmen who were jailed for a 2004 bomb attack on the Red Sea holiday resort of Taba. All 25 hostages were freed, unharmed, after only a day in captivity.
Katharina Gollner-Sweet, a spokeswoman for the U.S. Embassy in Cairo, confirmed that two American women had been kidnapped but gave no further details, citing privacy concerns, CBS News reported.
Egyptian Tourism Minister Munir Fakhri Abdul Nour said he had spoken to the Americans, and that they had assured him that they were in good health and had not been mistreated, BBC News reported.
More from GlobalPost: Chinese workers kidnapped by Bedouin in Sinai
Armed with machine guns, the attackers first took the tourists' money and valuables, then grabbed the women and the guide "as an apparent afterthought," security officials told Reuters.
The hostages were loaded into the gang's vehicles, which were seen driving into the mountains.
The brazen daylight abduction along a busy highway was a new blow to Egypt's vital tourism industry, which taken a grave hit since last year's uprising that ousted former President Hosni Mubarak, CBS reported.
Tensions across Egypt have spiked since a deadly soccer riot on Wednesday that has fueled anger at the ruling military council, as protesters accused police of standing by and allowing the bloodshed.
More from GlobalPost: Egypt: Soccer riots kill at more than 70 (VIDEO)