In my opinion this is an adult of wood-boring beetle (Buprestidae) belonging to the tribe Acmaeoderini (cfr genus Acmaeodera or other related genera). Regards,
Your beetle belongs to the Buprestidae family, then you need the opinion from a specialist but I would search in the genus Acmaeodera, Acmaeoderella, or related genus.
EDIT : I probably typed my message at the same time than Rinaldo, I had not seen his answer. So sorry for the duplicate, but I'm glad we agree on this one :)
It seems to be an Acmaeoderella, but I do not think even Mark Volkovitsh - the world-best expert in that group - would be able to reliably identify the species from these pictures...
Buprestidae: Polycestinae: Acmaeoderini: Acmaeoderina: Acmaeoderella (Euacmaeoderella) vetusta (Menetries, 1832). Larval host plant is unknown but it is not Astragalus.
Dear Shokoofeh, You can find some references to Astragalus associated Buprestidae in Annotated Catalogue of Buprestidae from Iran (Ghahari et al/. 2015). It seems I have sent it to you earlier, if not - let me know,
Dear Professor Mark, I am really appreciated all of your helps to me. You have already told me about Ghahari et al., 2015 manuscript and I have downloaded it! I read the manuscript and I found that no host plant was mentioned about this beetle! It makes my work more difficult because I collected it on Astragalus!
Dear Shokoofeh. I have a note in my files that A. vetusta was reared from Eryngium sp. (Apiales: Apiaceae) by P. Kabatek in Iran. I suppose it is a larval host plant for this species. Adults are visiting the flowers of different plants, mainly Asteraceae and Apiaceae, but also plants from other families. So, most probable, it is only a visiter of Astragalus flowers.
I am going to field in coming weeks and I will search for plants Eryngium if the weather is nice. For sure you are right and it was just a visitor. Thanks again for being patient with my a lot questions...