CHIANG MAI, Thailand — Former U.S. President Jimmy Carter said Monday he had no regrets about his handling of the Iran hostage crisis more than 30 years ago, saying he didn't attack the country as his advisers proposed because thousands of people would have died.

Islamic militants stormed the U.S. Embassy in Tehran on Nov. 4, 1979, and seized its occupants. Fifty-two Americans were held hostage for 444 days.

Carter acknowledged that his failure to bring the hostages home — including a botched rescue mission in which eight U.S. servicemen died — led to his election defeat to President Ronald Reagan in 1980. The hostages were released on Jan. 20, 1981, just minutes after Reagan was sworn in as the new president.

"I don't have any doubt that was the main factor in my defeat," Carter told reporters in the northern Thai city of Chiang Mai, where he was helping build houses for Habitat for Humanity. "Obviously, if I had rescued the hostages or they had not been taken, I would have been re-elected."

Carter said one proposed option was a military strike on Iran, but he chose to stick with negotiations to prevent bloodshed and bring the hostages home safely.

"My main advisers insisted that I should attack Iran," he said. "I could have destroyed Iran with my weaponry. But I felt in the process it was likely the hostages' lives would be lost, and I didn't want to kill 20,000 Iranians. So I didn't attack."

Carter and his wife, Rosalynn, are among 3,000 volunteers from 25 countries working with Habitat for Humanity this week to help build and repair homes along the Mekong River in Thailand, Vietnam, China, Cambodia and Laos.

The homes in Cambodia are being built for families currently living in a garbage dump, the ones in Vietnam are for fishermen who now live on their boats, and the project in China involves construction of an apartment building in a part of Sichuan province devastated by a 2008 earthquake.

"In an area of the world where many people live in deplorable conditions, we have a chance to help families improve their housing," said Carter, wearing sneakers, jeans and a work shirt. He and his wife spent Monday helping build 82 homes in honor of Thai King Bhumibol Adulyadej, who celebrates his 82nd birthday next month.

Habitat for Humanity's Chief Executive Officer Jonathan Reckford said the Georgia-based nonprofit group would construct houses for 50,000 families in the Mekong region over the next five years.