Iran has obtained data from a US intelligence drone that shows it was spying on the country's military sites and oil terminals, Iranian media reported its armed forces as saying on Wednesday.
Iran announced on Tuesday that it had captured a ScanEagle drone belonging to the United States, but Washington said there was no evidence to support the assertion.
The incident has underscored tensions in the Gulf as Iran and the United States draw attention to their military capabilities in the vital oil exporting region in a standoff over Iran's disputed nuclear program.
"We have fully extracted the drone's information," Iran's Islamic Revolutionary Guard Corps (IRGC) said in a statement on Wednesday, according to Iran's English-language Press TV.
The drone was gathering military information and spying on the transfer of oil from Iran's petroleum terminals, the IRGC statement said, according to Press TV. Iran's main export terminal is at Kharg Island.
The US government has focused on blocking Iran's oil exports through sanctions to persuade Iran to give up its disputed nuclear program, which the US and its allies believe is aimed at developing a bomb, something Iran denies.
Israeli officials have threatened to strike Iran's nuclear sites if sanctions and diplomacy fail to stop its program.
Iran has repeatedly threatened to close the Strait of Hormuz - through which about 40 percent of the world's seaborne crude oil is shipped - if it comes under attack. US commanders have said they will not let that happen.
The compact ScanEagle drone had been flying over the Gulf in the last few days and was captured when it strayed into Iranian airspace, the IRGC said in a statement on Tuesday.
The US military has been using Boeing Co ScanEagle spy planes since 2004 and they have become a relatively inexpensive way for the United States and others to conduct surveillance.
In November, the United States said Iranian warplanes shot at a US surveillance drone flying in international airspace.
Iran said the aircraft had entered its airspace to spy on Iranian oil platforms and said it would respond "decisively" to any incursions.
In December 2011, Iran said it had captured a US RQ-170 reconnaissance drone in eastern Iran which was reported lost by US forces in neighbouring Afghanistan.
Iranian commanders have since announced they have extracted valuable technology from the aircraft and were in the process of reverse-engineering it for their own defence industry.