Updated

American officials considered conducting a covert mission inside Iran to retrieve or destroy a stealth drone that crashed late last week -- but ultimately concluded such a secret operation was not worth the risk of provoking a more explosive clash with Tehran, a U.S. official said.

Tehran says it shot down the unmanned craft. But the U.S. source said the drone developed mechanical difficulties and remote pilots lost control of it -- and officials knew immediately it had gone down in eastern Iran.

The RQ-170 stealth drone was developed for the air force, but was flying under the authority of the Central Intelligence Agency when its remote pilots lost control of it late last week, according to several U.S. officials.

Initially, Washington officials didn't believe Iran had detected the crash, and considered various options for retrieving the wreckage.

Under one plan, a team would be sent to retrieve the aircraft. U.S. officials considered both sending in a team of American commandos based in Afghanistan as well as using allied agents inside Iran to get the downed aircraft.

Another alternative would have had a team sneak in to blow up the remaining pieces of the drone. A third option would have been to destroy the wreckage with an airstrike. However, the officials worried that any option for retrieving or destroying the drone would have risked discovery by Iran.

"No one warmed up to the option of recovering it or destroying it because of the potential it could become a larger incident," the U.S. official said. If an assault team entered the country to recover or destroy the drone, the official said, the U.S. "could be accused of an act of war" by the Iranian government.

To read more on this story, see The Wall St. Journal article here.