The offending act came during a meeting after a ceremony in which Swedish ambassador Peter Tejler presented Iranian President Mahmoud Ahmadinejad with his credentials, The Local.se reported.
Iranian website Asriran.com posted photos from the meeting in which Tejler is sitting cross-legged, but in the photos, Ahmadinejad is also seen crossing his legs.
Armenian website Panorama translated Asriran.com's report, which explains that sitting cross-legged "contradicts international diplomatic norms."
"Mahmoud Ahmadinejad, for his part, himself crossed his legs in response to the impoliteness of his interlocutor," the Asriran.com report said.
The Atlantic Wire, from University of West Florida, said showing the soles of one's feet is considered offensive in Muslim culture.
"Pointing the soles of the feet towards someone is impolite because the soles of the feet [shoe] are considered dirty, closest to the ground, closer to the devil and farther away from God. When in the presence of Muslims, be careful not to raise or cross your legs in such a way that the sole of the foot faces others in the room," The Atlantic Wire said.