Iran on Thursday blamed Israel for a drone attack that took place Saturday in the central Iranian city of Isfahan.
A letter posted on the website of Iran's mission to the United Nations said preliminary indications were that Israel "was responsible for this attempted act of aggression."
The letter did not include specific evidence.
Iran said the attack involved three drones that targeted a military workshop, and that two of them were shot down.
Iran's defense ministry said the attack caused minor damage to the building.
Israel has conducted a number of attacks targeting sites linked to Iran's nuclear program.
Some information for this report came from The Associated Press and Agence France-Presse.