President Barack Obama has said the US government has requested that Tehran return the surveillance drone captured by Iran's military earlier this month.
Mr Obama said he would not comment on classified intelligence matters, but confirmed: "We have asked for it back. We'll see how the Iranians respond."
Iranian TV broadcast pictures of the intact RQ-170 Sentinel last week.
Tehran said the aircraft was brought down using electronic warfare; Washington insisted it malfunctioned.
Earlier on Monday, Iranian state TV reported that military experts were in the final stages of recovering data from the drone.
A member of the Iranian parliament's national security committee, Parviz Sorouri, said the information they extracted would be used to "file a lawsuit against the United States over the invasion" by the aircraft.
US Secretary of State Hillary Clinton admitted that she did not think it likely that the drone would be returned.
"We are very clearly making known our concerns. We submitted a formal request for the return of our lost equipment, as we would in any situation. Given Iran's behaviour to date, we do not expect them to reply," she said.
She said that despite numerous "provocations" from Iran, the US would continue to pursue a "diplomatic approach".
The Revolutionary Guards, whose officers were filmed inspecting the drone on Thursday, said it crossed Iran's eastern border with Afghanistan and travelled 250km (155 miles) inside its airspace, before being brought down in a cyber attack.
However, US officials have said that intelligence assessments indicated that Iran neither shot down the aircraft nor used electronic warfare or cyber-technology to force it from the sky. They blamed a malfunction.
They are, however, concerned that Iran or its allies may be able to determine the chemical composition of the drone's radar-deflecting paint, or copy its engine, control systems, and sophisticated cameras and sensors, which allow it to monitor the ground from high altitude.
The Iranian government has sent a letter of protest to the United Nations, accusing the US of "provocative and secret actions" violating international law, and warning against any "repetition of such actions".
A former US official has said the Pentagon was using the drone to keep watch on Iran's controversial nuclear programme. Western powers believe Iran is trying to develop nuclear weapons, which it denies.